This research was funded by the International Research Training Group (IRTG) &#8220;Diffusion in porous Materials&#8221;. We acknowledge the technical support from Gert Klotzsche and stimulating discussions with Steven Reichhardt, Thomas Meissner, Damian Rybicki, Tobias Herzig, Natalya Georgieva, Jonas Kohlrautz, and Michael Jurkutat.

1 Montage et alignement des 6H-SiC grand cône Enclumes Boehler-Type <ol><li> Fixer le piston et la plaque xy dans les outils de montage et insérer les enclumes Boehler type dans le coin salon. </li><li> Assurez-vous que chaque enclume repose fermement dans les plaques d&#39;appui. </li><li> Avec de la résine époxy, (par exemple, Stycast 1266), coller les deux enclumes à leurs sièges. Cure de 12 h à température ambiante, ou 65 ° C dans un four pendant 2 heures. </li><li> Pour un alignement d&#39;enclume suffisante, utiliser les vis de réglage M1 à aligner les plaques d&#39;appui et de contrôler le parallélisme des deux enclumes. Si les enclumes ont été jugées non-parallèle, enlever la résine époxy et redémarrer au point 1.2. </li></ol> 2 Joint Préparation <ol><li> Drill 1 mm trous dans une puce de recuit Cu-Be (Cu 98% en poids, de 2% en poids, épaisseur de 0,5 mm) pour les broches de guidage en laiton. </li><li> Insérez trois 5 mm de long morceaux de fil non isolé d&#39;un diamètre de 1 mm de cuivre dans les trous, qui sont répartis le long de l&#39;enclume, pour servir guidles repères de e pour le joint Cu-Be. </li><li> Vérifier mise à la terre entre les broches de guidage et le corps de la cellule. Typiquement, une résistance en courant continu de l&#39;ordre de 0,1 Ω est souhaitée. Amélioration de l&#39;application d&#39;une petite quantité d&#39;argent conductrice. </li><li> Placer le manchon de Cu-Be sur le dessus de l&#39;enclume moissanite et fermer la cellule. </li><li> En utilisant une presse hydraulique, pression sur le joint à environ 1/8 ème du diamètre colette pour la stabilité de travail maximisée. Surveiller l&#39;épaisseur réelle de l&#39;empreinte à l&#39;aide d&#39;un pied à coulisse micrométrique. </li><li> Percer un trou de diamètre approprié (la moitié du diamètre de colette) dans le centre de l&#39;empreinte. </li><li> Découper deux canaux dans le joint pré-découpée. Les canaux doivent être suffisamment profonde pour recevoir le fil de cuivre de 18 um de la micro-bobine. </li><li> Harden le joint d&#39;étanchéité prêt à 617 K pendant 2 à 3 heures dans un four. </li></ol> 3 Préparation et chargement de la micro-bobine <ol><li> Utilisez un morceau de 1 mm d&#39;un fil de cuivreD passer par la traversée du piston. Fixer le fil de cuivre avec une résine époxy et guérir selon l&#39;étape 1.3. </li><li> Choisissez un poinçon (voir la liste des matériaux) qui a le diamètre souhaité pour la micro-bobine et le fixer entre une paire de Chuck-mâchoires rotatives. </li><li> Colle (avec, par exemple, vernis de SCB, voir la liste des matériaux) une extrémité du fil 18 um de cuivre sur les mors, tout en maintenant l&#39;autre extrémité et tourner la mâchoire de serrage pour que le fil est enroulé sur le poinçon. </li><li> Lorsque la micro-bobine est de la géométrie souhaitée, fixer l&#39;autre extrémité du fil sur la colle aussi bien. </li><li> Utilisation vernis dilué à fixer la bobine par l&#39;application d&#39;une petite quantité au-dessus des enroulements. </li><li> Retirer la bobine soin du poinçon avec du ruban téflon. </li><li> Mettre un peu de résine époxy (voir point 1.3), sans aucun additif, dans les canaux de la garniture. </li><li> Passer au micro-bobine à l&#39;intérieur de la chambre d&#39;échantillon et fixer les fils dans les canaux. </li><li> Guérissez les epoxy résine selon l&#39;étape 1.3. </li><li> Souder un fil de la micro-bobine à fil chaud et l&#39;autre à une tige de guidage. </li><li> Ajoutez un peu de pâte conductrice d&#39;argent sur le dessus de chaque jonction. Guérir prend généralement quelques minutes. </li><li> Sceller les deux jonctions avec une petite quantité de résine époxy. </li><li> Guérir l&#39;époxy selon l&#39;étape 1.3. </li><li> Maintenant, vérifier la résistance DC de la bobine après chaque étape. </li><li> Placer l&#39;échantillon dans la micro-bobine. Soyez conscient que tout contact physique inutile peut détruire la bobine. </li><li> Ajouter la poudre de rubis finement moulu à l&#39;échantillon pour l&#39;étalonnage de pression. </li><li> Enfin, inonder la chambre de l&#39;échantillon avec un milieu de pression approprié. Utilisez l&#39;huile de paraffine pour assurer des conditions quasi-hydrostatiques jusqu&#39;à 9 GPa. </li><li> Fermez avec précaution la cellule. </li></ol> 4 Application et contrôle de la pression <ol><li> Dans un premier temps, serrez légèrement les vis à tête fraisée M3 Allen. </li><li> Pour fixer la pressurisation de la cellule dans un étau. Maintenant, serrezdeux vis opposées deux à deux. </li><li> Placez la cellule sous pression dans un porte-cellule appropriée. </li><li> Ajuster la position de la cellule de sorte que le faisceau laser atteigne la chambre de mesure. </li><li> Utilisez le tableau de réglage fin pour concentrer la poudre de rubis dans le faisceau laser. </li><li> Surveiller le rubis spectre de photoluminescence en utilisant le logiciel correspondant spectromètre. </li><li> Extraire la pression réelle dans la cavité d&#39;échantillon à partir du décalage spectral observé des lignes rubis R1 et R2. </li><li> Equilibrer la cellule sous pression pendant au moins 12 heures avant les mesures de RMN sont démarrés. </li></ol> 5. réaliser des expériences de RMN <ol><li> Monter la cellule de pression sur une sonde RMN typique. Fabrication détenteurs de cellules appropriées dans un atelier de mécanique. </li><li> Soudez le fil chaud à la sonde. Vérifiez contact électrique entre la cellule et la sonde. </li><li> Maintenant, réaliser des expériences de RMN standard. Attirer l&#39;attention sur le fait que la micro-bobine est very sensible à l&#39;énergie de radio-fréquence appliquée. </li></ol>

<ol>
	<li>Hemley, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Percy+Bridgman&#180;s+Second+Century.">Percy Bridgman&#180;s Second Century.</a> High Pressure Research. 30 (4), 581-619 (2010).</li><li>Grochala, W., Hoffmann, R., Feng, J., Ashcroft, N. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Chemical+imagination+at+work+in+very+tight+places.">The Chemical imagination at work in very tight places.</a> Angewandte Chemie (International Edition in English). 46 (20), 3620-3642 (2007).</li><li>Ma, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transparent+dense+sodium.">Transparent dense sodium.</a> Nature. 458 (7235), 182-185 (2009).</li><li>Eremets, M. I., Troyan, I. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conductive+dense+hydrogen.">Conductive dense hydrogen.</a> Nat Mater. 10 (12), 927-931 (2011).</li><li>Jayaraman, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diamond+anvil+cell+and+high-pressure+physical+investigations.">Diamond anvil cell and high-pressure physical investigations.</a> Rev Mod Phys. 55 (1), 65-108 (1983).</li><li>Bertani, R., Mali, M., Roos, J., Brinkmann, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+diamond+anvil+cell+for+high-pressure+NMR+investigations.">A diamond anvil cell for high-pressure NMR investigations.</a> Rev Sci Instrum. 63 (6), 3303 (1992).</li><li>Lee, S. -. H., Luszczynski, K., Norberg, R. E., Conradi, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NMR+in+a+diamond+anvil+cell.">NMR in a diamond anvil cell.</a> Rev Sci Instrum. 58 (3), 415 (1987).</li><li>Lee, S. -. H., Conradi, M. S., Norberg, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+NMR+resonator+for+diamond+anvil+cells.">Improved NMR resonator for diamond anvil cells.</a> Rev Sci Instrum. 63 (7), 3674 (1992).</li><li>Pravica, M. G., Silvera, I. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+magnetic+resonance+in+a+diamond+anvil+cell+at+very+high+pressures.">Nuclear magnetic resonance in a diamond anvil cell at very high pressures.</a> Rev Sci Instrum. 69 (2), 479 (1998).</li><li>Lee, S. -. H., Conradi, M., Norberg, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+motion+in+solid+H2+at+high+pressures.">Molecular motion in solid H2 at high pressures.</a> Phys Rev B. 40 (18), 12492-12498 (1989).</li><li>Vaughan, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Apparatus+for+Magnetic+Measurements+at+High+Pressure.">An Apparatus for Magnetic Measurements at High Pressure.</a> Rev Sci Instrum. 42 (5), 626 (1971).</li><li>Yarger, J. L., Nieman, R. A., Wolf, G. H., Marzke, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-Pressure+1H+and+13C+Nuclear+Magnetic+Resonance+in+a+Diamond+Anvil+Cell.">High-Pressure 1H and 13C Nuclear Magnetic Resonance in a Diamond Anvil Cell.</a> Journal of Magnetic Resonance Series A. 114 (2), 255-257 (1995).</li><li>Okuchi, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+type+of+nonmagnetic+diamond+anvil+cell+for+nuclear+magnetic+resonance+spectroscopy.">A new type of nonmagnetic diamond anvil cell for nuclear magnetic resonance spectroscopy.</a> Physics of the Earth and Planetary Interiors. , 143-144 (2004).</li><li>Kluthe, S., Markendorf, R., Mali, M., Roos, J., Brinkmann, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pressure-dependent+Knight+shift+in+Na+and+Cs+metal.">Pressure-dependent Knight shift in Na and Cs metal.</a> Phys Rev B. 53 (17), 11369-11375 (1996).</li><li>Graf, D. E., Stillwell, R. L., Purcell, K. M., Tozer, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonmetallic+gasket+and+miniature+plastic+turnbuckle+diamond+anvil+cell+for+pulsed+magnetic+field+studies+at+cryogenic+temperatures.">Nonmetallic gasket and miniature plastic turnbuckle diamond anvil cell for pulsed magnetic field studies at cryogenic temperatures.</a> High Pressure Research. 31 (4), 533-543 (2011).</li><li>Pravica, M., Silvera, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NMR+Study+of+Ortho-Para+Conversion+at+High+Pressure+in+Hydrogen.">NMR Study of Ortho-Para Conversion at High Pressure in Hydrogen.</a> Physical Review Letters. 81 (19), 4180-4183 (1998).</li><li>Haase, J., Goh, S. K., Meissner, T., Alireza, P. L., Rybicki, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+sensitivity+nuclear+magnetic+resonance+probe+for+anvil+cell+pressure+experiments.">High sensitivity nuclear magnetic resonance probe for anvil cell pressure experiments.</a> Rev Sci Instrum. 80 (7), 73905 (2009).</li><li>Meissner, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+Approach+to+High-Pressure+Nuclear+Magnetic+Resonance+with+Anvil+Cells.">New Approach to High-Pressure Nuclear Magnetic Resonance with Anvil Cells.</a> J Low Temp Phys. 159 (1-2), 284-287 (2010).</li><li>Meier, T., Herzig, T., Haase, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Moissanite+Anvil+Cell+Design+for+Giga-Pascal+Nuclear+Magnetic+Resonance.">Moissanite Anvil Cell Design for Giga-Pascal Nuclear Magnetic Resonance.</a> Rev Sci Instrum. 85 (4), 43903 (2014).</li><li>Boyer, R. F., Collings, E. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Materials Properties Handbook: Titanium Alloys. , (1994).</li><li>Xu, J. -. a., Yen, J., Wang, Y., Huang, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrahigh+pressures+in+gem+anvil+cells.">Ultrahigh pressures in gem anvil cells.</a> High Pressure Research. 15 (2), 127-134 (1996).</li><li>Xu, J. -. a., Mao, H. -. k., Hemley, R. J., Hines, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+moissanite+anvil+cell+a+new+tool+for+high-pressure+research.">The moissanite anvil cell a new tool for high-pressure research.</a> J Phys Condens Matter. 14 (44), 11543-11548 (2002).</li><li>Xu, J. -. a., Mao, H. -. k., Hemley, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+gem+anvil+cell+high-pressure+behaviour+of+diamond+and+related+materials.">The gem anvil cell high-pressure behaviour of diamond and related materials.</a> J Phys Condens Matter. 14 (44), 11549-11552 (2002).</li><li>Meissner, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+magnetic+resonance+at+up+to+10.1+GPa+pressure+detects+an+electronic+topological+transition+in+aluminum+metal.">Nuclear magnetic resonance at up to 10.1 GPa pressure detects an electronic topological transition in aluminum metal.</a> J Phys Condens Matter. 26 (1), 15501 (2014).</li><li>Meissner, T., Goh, S. K., Haase, J., Williams, G. r. a. n. t. . V. M., Littlewood, P. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-pressure+spin+shifts+in+the+pseudogap+regime+of+superconducting+YBa2Cu4O8+as+revealed+by+17O+NMR.">High-pressure spin shifts in the pseudogap regime of superconducting YBa2Cu4O8 as revealed by 17O NMR.</a> Phys Rev B. 83 (22), (2011).</li><li>Goh, S. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+pressure+de+Haas&#8211;van+Alphen+studies+of+Sr2RuO4+using+an+anvil+cell.">High pressure de Haas&#8211;van Alphen studies of Sr2RuO4 using an anvil cell.</a> Current Applied Physics. 8 (3-4), 304-307 (2008).</li><li>Tateiwa, N., Haga, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluations+of+pressure-transmitting+media+for+cryogenic+experiments+with+diamond+anvil+cell.">Evaluations of pressure-transmitting media for cryogenic experiments with diamond anvil cell.</a> Rev Sci Instrum. 80 (12), 123901 (2009).</li><li>Hahn, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spin+Echoes.">Spin Echoes.</a> Phys Rev. 80 (4), 580-594 (1950).</li><li>Boehler, R., Ross, M., Boercker, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Melting+of+LiF+and+NaCl+to+1+Mbar+Systematics+of+Ionic+Solids+at+Extreme+Conditions.">Melting of LiF and NaCl to 1 Mbar Systematics of Ionic Solids at Extreme Conditions.</a> Physical Review Letters. 78 (24), 4589-4592 (1997).</li><li>Funamori, N., Sato, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+cubic+boron+nitride+gasket+for+diamond-anvil+experiments.">A cubic boron nitride gasket for diamond-anvil experiments.</a> Rev Sci Instr. 79 (5), 053903 (2008).</li><li>Forman, R. A., Piermarini, G. J., Barnett, J. D., Block, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pressure+measurement+made+by+the+utilization+of+ruby+sharp-line+luminscence.">Pressure measurement made by the utilization of ruby sharp-line luminscence.</a> Science. 176 (4032), 284-285 (1972).</li></ol>

The authors have nothing to disclose.

Une méthode nouvelle et prometteuse pour effectuer RMN à des pressions Giga-Pascal a été décrite. Cette méthode ouvre la porte à un large éventail d&#39;expériences de RMN en raison de son excellente sensibilité et la résolution. Néanmoins, plusieurs étapes décrites dans la section du protocole sont cruciales pour l&#39;issue de l&#39;expérience. Surtout, la préparation de la micro-bobine et sa fixation dans le joint Cu-Be est très difficile et nécessite une certaine expérience. Dans ce qui suit, quel...

Depuis les expériences de cachet de Percy Bridgman de la matière condensée sous des pressions hydrostatiques élevées au début du siècle dernier, le domaine de la physique à haute pression a évolué rapidement 1. Un grand nombre de phénomènes intrigants sont connus pour être sous la pression de plusieurs GPa 2. En outre, la réponse des systèmes de la matière condensée à haute pression nous a appris beaucoup de choses sur leur sol électronique et états excités 3,4. Malheureusement, les techniques de l&#39;étude des propriétés électroniques de la matière condensée à des pressions Giga-Pascal sont rares, avec x-ray ou des mesures de résistance DC ouvrent la voie 5. En particulier, la détection des moments magnétiques électroniques ou nucléaires de spin électronique (ESR) ou la résonance magnétique nucléaire (RMN) des expériences, est tenu d&#39;être presque impossible à mettre en œuvre dans un cadre typiquement cellules à enclumes à haute pression où on a besoin de récupérer le signal de un petit volume consacré par enclumes et un joint d&#39;étanchéité. Plusieurs groupes ont tenté de résoudre ce problème en utilisant des arrangements complexes, par exemple, deux split-paire de radiofréquence (RF) bobines enroulées le long des flancs des enclumes 6; une boucle simple ou double épingle à cheveux résonateur 7,8; . ou même un joint fendu de rhénium comme une bobine RF pick-up 9, voir la figure 1 Malheureusement, ces approches toujours souffert d&#39;un faible rapport signal sur bruit (SNR), ce qui limite les applications expérimentales à grande - γ noyaux tels que 1 H 10. Le lecteur intéressé peut être soumis à d&#39;autres expériences de résonance du circuit de réservoir haute pression 11 - 15. Pravica et Silvera 16 rapport de la pression la plus élevée atteinte dans un cellule à enclume de RMN 12,8 GPa, qui a étudié la conversion ortho-para de l&#39;hydrogène. Avec un grand intérêt dans l&#39;application de la RMNd&#39;étudier les propriétés des solides quantiques, notre groupe était intéressé à avoir RMN disponibles à des pressions élevées, aussi bien. Enfin, en 2009, il a pu être démontré que haute sensibilité RMN de cellule à enclume est en effet possible que si une résonance radiofréquence (RF) micro-bobine est placée directement dans la cavité haute pression entourant l&#39;échantillon 17. Dans une telle approche, la sensibilité de la RMN est améliorée par plusieurs ordres de grandeur (la plupart du temps en raison de l&#39;augmentation considérable de facteur de remplissage de la bobine RF), qui fait des expériences de RMN encore plus difficile possible, par exemple, 17 O RMN sur des échantillons de poudre d&#39;un supraconducteur à haute température jusqu&#39;à 7 GPa 18. Supraconductivité dans ces matériaux peut être considérablement amplifiée par l&#39;application de la pression, et il est maintenant possible de suivre ce processus avec une sonde électronique locale qui promet idée fondamentale dans les processus régissant. Un autre exemple de la puissance de la RMN sous haute pression a émergé de ce qui était la croyanted à être des expériences de référencement de routine: afin de tester le nouveau RMN de cellule à enclume en place, l&#39;un des matériaux les plus connus a été mesurée - de l&#39;aluminium métallique simple. Comme la pression a été augmentée, une déviation inattendue du changement RMN de ce que l&#39;on pourrait s&#39;attendre pour un système à électrons libres a été trouvé. Expériences répétées, y compris sous des pressions accrues, ont montré que les nouveaux résultats sont effectivement fiables. Enfin, avec les calculs de structure de bandes, il a ensuite constaté que les résultats sont la manifestation d&#39;une transition topologique de la surface de Fermi de l&#39;aluminium, qui ne pouvait pas être détecté par des calculs il ya des années, quand la puissance de calcul est faible. L&#39;extrapolation des résultats à des conditions ambiantes ont montré que les propriétés de ce métal qui est utilisé presque partout sont influencés par cette condition électronique spéciale. Afin de poursuivre un certain nombre d&#39;applications différentes cellules enclume spécialement conçus (cellules précédentes avaient été importés de la Cavendish laboratoire et réadaptés pour RMN) ont été développés. Actuellement, le châssis de la maison construite utilisés sont capables d&#39;atteindre des pressions allant jusqu&#39;à 25 GPa en utilisant une paire de 800 um de culasse enclumes 6H-SiC. Expériences de RMN ont été réalisées avec succès à 10,1 GPa, à ce jour. Les performances de ce nouveau RMN cellules s&#39;est avérée excellente 19. Le composant principal est en titane-aluminium (6) -Vanadium (4) avec un faible niveau interstitiel supplémentaire (grade 23), fournissant une limite d&#39;élasticité d&#39;environ 800 MPa 20. En raison de ses propriétés non-magnétiques (susceptibilité χ l&#39;magnétique est d&#39;environ 5 ppm), il s&#39;agit d&#39;un matériau adéquat pour le châssis de cellule enclume. Les dimensions globales des cellules introduites (voir la figure 2 pour un aperçu de tous enclume conceptions de cellules assemblés) sont suffisamment petits pour tenir dans standards réguliers aimants de RMN de l&#39;alésage. Le design le plus petit, le LAC-TM1, qui est à seulement 20 mm de hauteur et 17 mm de diamètre, convient aussi de petits aimants froid calibre typiques (diamètre d&#39;alésage de 30 mm). La LAC-TM2, qui est le dernier châssis les auteurs ont conçu, utilise quatre boulons à tête fraisée M4 Allen (fabriqués à partir du même alliage que le châssis de la cellule) comme mécanisme d&#39;entraînement de pression, ce qui permet un contrôle régulier de la pression interne (bleus attachés à section supplémentaire). Typiquement, les enclumes de diamant sont utilisés afin de générer des pressions plus élevées au-dessus de 100 GPa. Xu et Mao 21-23 ont démontré que des enclumes moissanite offrent une alternative rentable à la recherche de haute pression, jusqu&#39;à des pressions de l&#39;ordre de 60 GPa. Par conséquent, enclumes moissanite ont été utilisés pour l&#39;approche GPa RMN introduit. Les meilleurs résultats ont été obtenus avec personnalisés enclumes grand cône 6H-SiC du département de l&#39;enclume de Charles &amp; Colvard. Avec ces cellules, pour des pressions allant jusqu&#39;à 10,1 GPa, l&#39;utilisation de 800 um enclumes de culasse a été trouvé pour aboutir à une très bonne sensibilité RMN. A titre de comparaison, Lee et al. Signaler un SNR de 1 pour 1 H NMR de l&#39;eau du robinet, tandis que le SNR de l&#39;approche micro-bobine introduit montré une valeur de 25 pour un septième de leur volume, même à un champ magnétique un peu plus bas. Avec cette nouvelle approche de la haute sensibilité cellule à enclume RMN, on peut poursuivre de nombreuses applications qui promettent un nouvel aperçu passionnant dans la physique et la chimie des matériaux modernes. Cependant, comme toujours, la sensibilité et la résolution limitent finalement l&#39;application de la RMN, en particulier, si l&#39;on s&#39;intéresse à des pressions beaucoup plus élevées que la demande de plus petites tailles de de culasse. Ensuite, on a non seulement pour optimiser la conception de la cellule avec encore plus petites bobines RF, mais aussi réfléchir à des méthodes pour accroître la polarisation nucléaire.

<table border="0" cellpadding="0" cellspacing="0" width="672">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Name of Material/ Equipment</td>
			<td style="width:147px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:164px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Titanium grade 23</td>
			<td style="width:147px;">robemetall GmbH</td>
			<td style="width:119px;">ASTM F 136</td>
			<td style="width:164px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Beryllium copper foil</td>
			<td style="width:147px;">GoodFellow</td>
			<td style="width:119px;">CU070501</td>
			<td>Alloy 25 (C17200)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Copper wire for micro-coil</td>
			<td style="width:147px;">Polyfil</td>
			<td style="width:119px;">--</td>
			<td>quote on inquiry</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Stycast 1266</td>
			<td style="width:147px;">Sil-Mid Ldt.</td>
			<td style="width:119px;">S1266001KG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Moissanite anvils</td>
			<td style="width:147px;">Charles &#38; Colvard</td>
			<td style="width:119px;">--</td>
			<td>quote on inquiry</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Paraffin oil (pressure medium)</td>
			<td style="width:147px;">Sigma Aldrich</td>
			<td style="width:119px;">18512-1L</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">M4 Allen contersunk screws (Ti64)</td>
			<td style="width:147px;">Der Schraubenladen</td>
			<td style="width:119px;">DIN912 M4x20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Optiprexx PLS</td>
			<td style="width:147px;">Almax-easylab</td>
			<td style="width:119px;">--</td>
			<td>quote on inquiry</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Ruby spheres (~10-50 &#181;m)</td>
			<td style="width:147px;">DiamondAnvils.com</td>
			<td style="width:119px;">P00996</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Manual Toggle Press</td>
			<td style="width:147px;">DiamondAnvils.com</td>
			<td style="width:119px;">A87000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Gasket Thickness Micrometer</td>
			<td style="width:147px;">DiamondAnvils.com</td>
			<td style="width:119px;">A86000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Titanium Scalpel&#160;</td>
			<td style="width:147px;">Newmatic Medical</td>
			<td style="width:119px;">NM45200710421&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Glass-writing Diamond</td>
			<td style="width:147px;">Plano</td>
			<td style="width:119px;">54467</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Smoothing Awls</td>
			<td style="width:147px;">Flume</td>
			<td style="width:119px;">1 4444 001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Chuck-jaws (4 jaws)</td>
			<td style="width:147px;">Flume</td>
			<td style="width:119px;">4 561 289</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Lathe</td>
			<td style="width:147px;">Flume</td>
			<td style="width:119px;">4 560 023</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Drilling Machine</td>
			<td style="width:147px;">Flume</td>
			<td style="width:119px;">4 570 020</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Drill chuck</td>
			<td style="width:147px;">Flume</td>
			<td style="width:119px;">4 570 021</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">XY stage</td>
			<td style="width:147px;">Flume</td>
			<td style="width:119px;">4 570 022</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Drills (0.30 to 0.50 mm)</td>
			<td style="width:147px;">Flume</td>
			<td style="width:119px;">4 572 652 &#8211; 654</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Low Temperature Varnish</td>
			<td style="width:147px;">SCBshop</td>
			<td style="width:119px;">SCBltv03</td>
			<td></td>
		</tr>
	</tbody>
</table>

high-sensitivity nuclear magnetic resonance at giga-pascal pressures: a new tool for probing electronic and chemical properties of condensed matter under extreme conditions

Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their electronic properties. The application of high pressure enables one to synthesize new materials, but the response of known materials to high pressure is a very useful tool for studying their electronic structure and developing theories. For example, high-pressure synthesis might be at the origin of life; and understanding the behavior of small molecules under extreme pressure will tell us more about fundamental processes in our universe. It is no wonder that there has always been great interest in having NMR available at high pressures. Unfortunately, the desired pressures are often well into the Giga-Pascal (GPa) range and require special anvil cell devices where only very small, secluded volumes are available. This has restricted the use of NMR almost entirely in the past, and only recently, a new approach to high-sensitivity GPa NMR, which has a resonating micro-coil inside the sample chamber, was put forward. This approach enables us to achieve high sensitivity with experiments that bring the power of NMR to Giga-Pascal pressure condensed matter research. First applications, the detection of a topological electronic transition in ordinary aluminum metal and the closing of the pseudo-gap in high-temperature superconductivity, show the power of such an approach. Meanwhile, the range of achievable pressures was increased tremendously with a new generation of anvil cells (up to 10.1 GPa), that fit standard-bore NMR magnets. This approach might become a new, important tool for the investigation of many condensed matter systems, in chemistry, geochemistry, and in physics, since we can now watch structural changes with the eyes of a very versatile probe.

La figure 3 montre comment la cellule de pression complètement assemblé, le câblage et la fixation sur une sonde RMN typique ressemblent. Par la suite, plusieurs expériences seront examinés, ce qui devrait permettre au lecteur de rassembler un large aperçu sur les avantages et les limites de la technique introduite. <img alt="Figure 1" src="/files/ftp_upload/52243/52243fig1highres.jpg" /> Figure 1: Différentes approch...

Watch this Scientific Journal Video about High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extr

High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions

Nuclear magnetic resonance is one of the most important spectroscopic tools. Here, the development of a new approach under high pressure, currently up to 10.1 GPa, is presented. This opens a new window into condensed matter physics and chemistry, where high-pressure research is of great importance.

Sensibilité élevée de résonance magnétique nucléaire à Giga-Pascal pressions: Un nouvel outil pour sonder les propriétés électroniques et chimiques de la matière condensée dans des conditions extrêmes

Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their ...

high-sensitivity-nuclear-magnetic-resonance-at-giga-pascal-pressures

Research

Education

JoVE Core

JoVE Journal

Analytical Chemistry

Engineering

Unit 1

Principles of Nuclear Magnetic Resonance

SCIENTISTS IN ACTION

11.5K vues.  University of Leipzig. Nuclear magnetic resonance is one of the most important spectroscopic tools. Here, the development of a new approach under high pressure, currently up to 10.1 GPa, is presented. This opens a new window into condensed matter physics and chemistry, where high-pressure research is of great importance.

Vidéo: High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions

Synthesis and Microdiffraction at Extreme Pressures and Temperatures

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary interiors, design materials with novel properties, understand the mechanical behavior of materials exposed to very high stresses as in explosions or impacts. Synthesis and structural analysis of materials at extreme conditions of pressure and temperature entails remarkable technical challenges. In the laser heated diamond anvil cell (LH-DAC), very high pressure is generated between the tips of two opposing diamond anvils forced against each other; focused infrared laser beams, shined through the diamonds, allow to reach very high temperatures on samples absorbing the laser radiation. When the LH-DAC is installed in a synchrotron beamline that provides extremely brilliant x-ray radiation, the structure of materials under extreme conditions can be probed in situ. LH-DAC samples, although very small, can show highly variable grain size, phase and chemical composition. In order to obtain the high resolution structural analysis and the most comprehensive characterization of a sample, we collect diffraction data in 2D grids and combine powder, single crystal and multigrain diffraction techniques. Representative results obtained in the synthesis of a new iron oxide, Fe4O5 1 will be shown.

The laser heated diamond anvil cell combined with synchrotron micro-diffraction techniques allows researchers to explore the nature and properties of new phases of matter at extreme pressure and temperature (PT) conditions. Heterogeneous samples can be characterized in situ under high pressure by 2D mapping and combined powder, single-crystal and multigrain diffraction approaches.

Synthèse et Microdiffraction à des pressions et des températures extrêmes

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary ...

Recherche

Ingénierie

Flame Experiments at the Advanced Light Source: New Insights into Soot Formation Processes

The following experimental protocols and the accompanying video are concerned with the flame experiments that are performed at the Chemical Dynamics Beamline of the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory1-4. This video demonstrates how the complex chemical structures of laboratory-based model flames are analyzed using flame-sampling mass spectrometry with tunable synchrotron-generated vacuum-ultraviolet (VUV) radiation. This experimental approach combines isomer-resolving capabilities with high sensitivity and a large dynamic range5,6. The first part of the video describes experiments involving burner-stabilized, reduced-pressure (20-80 mbar) laminar premixed flames. A small hydrocarbon fuel was used for the selected flame to demonstrate the general experimental approach. It is shown how species&#8217; profiles are acquired as a function of distance from the burner surface and how the tunability of the VUV photon energy is used advantageously to identify many combustion intermediates based on their ionization energies. For example, this technique has been used to study gas-phase aspects of the soot-formation processes, and the video shows how the resonance-stabilized radicals, such as C3H3, C3H5, and i-C4H5, are identified as important intermediates7. The work has been focused on soot formation processes, and, from the chemical point of view, this process is very intriguing because chemical structures containing millions of carbon atoms are assembled from a fuel molecule possessing only a few carbon atoms in just milliseconds. The second part of the video highlights a new experiment, in which an opposed-flow diffusion flame and synchrotron-based aerosol mass spectrometry are used to study the chemical composition of the combustion-generated soot particles4. The experimental results indicate that the widely accepted H-abstraction-C2H2-addition (HACA) mechanism is not the sole molecular growth process responsible for the formation of the observed large polycyclic aromatic hydrocarbons (PAHs).

Gas sampling from laboratory-scale flames with online analysis of all species by mass spectrometry is a powerful method to investigate the complex mixture of chemical compounds occurring during combustion processes. Coupled with tunable soft ionization via synchrotron-generated vacuum-ultraviolet radiation, this technique provides isomer-resolved information and potentially fragment-free mass spectra.

Les expériences de la flamme à l&#39;Advanced Light Source: nouvelles perspectives sur les processus d&#39;établissement de la suie

The following experimental protocols and the accompanying video are concerned with the flame experiments that are performed at the Chemical Dynamics ...

In Situ Neutron Powder Diffraction Using Custom-made Lithium-ion Batteries

Li-ion batteries are widely used in portable electronic devices and are considered as promising candidates for higher-energy applications such as electric vehicles.1,2 However, many challenges, such as energy density and battery lifetimes, need to be overcome before this particular battery technology can be widely implemented in such applications.3 This research is challenging, and we outline a method to address these challenges using in situ NPD to probe the crystal structure of electrodes undergoing electrochemical cycling (charge/discharge) in a battery. NPD data help determine the underlying structural mechanism responsible for a range of electrode properties, and this information can direct the development of better electrodes and batteries.
We briefly review six types of battery designs custom-made for NPD experiments and detail the method to construct the &#8216;roll-over&#8217; cell that we have successfully used on the high-intensity NPD instrument, WOMBAT, at the Australian Nuclear Science and Technology Organisation (ANSTO). The design considerations and materials used for cell construction are discussed in conjunction with aspects of the actual in situ NPD experiment and initial directions are presented on how to analyze such complex in situ data.

In Situ Neutron Powder Diffraction Using Custom-made Lithium-ion Batteries

We describe the design and construction of an electrochemical cell for the examination of electrode materials using in situ neutron powder diffraction (NPD). We briefly comment on alternate in situ NPD cell designs and discuss methods for the analysis of the corresponding in situ NPD data produced using this cell.

In Situ diffraction de poudre, l&#39;utilisation des batteries au lithium-ion sur mesure

Li-ion batteries are widely used in portable electronic devices and are considered as promising candidates for higher-energy applications such as electric ...

Resonance Raman Spectroscopy of Extreme Nanowires and Other 1D Systems

This paper briefly describes how nanowires with diameters corresponding to 1 to 5 atoms can be produced by melting a range of inorganic solids in the presence of carbon nanotubes. These nanowires are extreme in the sense that they are the limit of miniaturization of nanowires and their behavior is not always a simple extrapolation of the behavior of larger nanowires as their diameter decreases. The paper then describes the methods required to obtain Raman spectra from extreme nanowires and the fact that due to the van Hove singularities that 1D systems exhibit in their optical density of states, that determining the correct choice of photon excitation energy is critical. It describes the techniques required to determine the photon energy dependence of the resonances observed in Raman spectroscopy of 1D systems and in particular how to obtain measurements of Raman cross-sections with better than 8% noise and measure the variation in the resonance as a function of sample temperature. The paper describes the importance of ensuring that the Raman scattering is linearly proportional to the intensity of the laser excitation intensity. It also describes how to use the polarization dependence of the Raman scattering to separate Raman scattering of the encapsulated 1D systems from those of other extraneous components in any sample.

The paper describes a method for producing extreme nanowires by melt infiltration into carbon nanotubes and how 1D systems may be characterized and investigated using Resonance Raman Spectroscopy to determine vibrational and optical excitation energies.

Resonance Raman Spectroscopy de Extreme nanofils et autres systèmes 1D

This paper briefly describes how nanowires with diameters corresponding to 1 to 5 atoms can be produced by melting a range of inorganic solids in the ...

Use of a Multi-compartment Dynamic Single Enzyme Phantom for Studies of Hyperpolarized Magnetic Resonance Agents

Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due to fundamental constraints imposed by the hyperpolarized state, exotic imaging and reconstruction techniques are commonly used. A practical system for characterization of dynamic, multi-spectral imaging methods is critically needed. Such a system must reproducibly recapitulate the relevant chemical dynamics of normal and pathological tissues. The most widely utilized substrate to date is hyperpolarized [1-13C]-pyruvate for assessment of cancer metabolism. We describe an enzyme-based phantom system that mediates the conversion of pyruvate to lactate. The reaction is initiated by injection of the hyperpolarized agent into multiple chambers within the phantom, each of which contains varying concentrations of reagents that control the reaction rate. Multiple compartments are necessary to ensure that imaging sequences faithfully capture the spatial and metabolic heterogeneity of tissue. This system will aid the development and validation of advanced imaging strategies by providing chemical dynamics that are not available from conventional phantoms, as well as control and reproducibility that is not possible in vivo.

A multi-compartment dynamic phantom is used to simulate some biology of interest for metabolic studies using hyperpolarized magnet resonance agents.

Utilisation d&#39;un multi-compartiment dynamique unique Enzyme Phantom pour les études de hyperpolarisé Agents de résonance magnétique

Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due ...

In Situ Visualization of the Phase Behavior of Oil Samples Under Refinery Process Conditions

To help address production issues in refineries caused by the fouling of process units and lines, we have developed a setup as well as a method to visualize the behavior of petroleum samples under process conditions. The experimental setup relies on a custom-built micro-reactor fitted with a sapphire window at the bottom, which is placed over the objective of an inverted microscope equipped with a cross-polarizer module. Using reflection microscopy enables the visualization of opaque samples, such as petroleum vacuum residues, or asphaltenes. The combination of the sapphire window from the micro-reactor with the cross-polarizer module of the microscope on the light path allows high-contrast imaging of isotropic and anisotropic media. While observations are carried out, the micro-reactor can be heated to the temperature range of cracking reactions (up to 450 &#176;C), can be subjected to H2 pressure relevant to hydroconversion reactions (up to 16 MPa), and can stir the sample by magnetic coupling. 
Observations are typically carried out by taking snapshots of the sample under cross-polarized light at regular time intervals. Image analyses may not only provide information on the temperature, pressure, and reactive conditions yielding phase separation, but may also give an estimate of the evolution of the chemical (absorption/reflection spectra) and physical (refractive index) properties of the sample before the onset of phase separation.

In Situ Visualization of the Phase Behavior of Oil Samples Under Refinery Process Conditions

This article describes a setup and method for the in situ visualization of oil samples under a variety of temperature and pressure conditions that aim to emulate refining and upgrading processes. It is primarily used for studying isotropic and anisotropic media involved in the fouling behavior of petroleum feeds.

In Situ Visualisation du comportement des échantillons de pétrole Phase Sous raffinerie processus Conditions

To help address production issues in refineries caused by the fouling of process units and lines, we have developed a setup as well as a method to ...

A Novel Biaxial Testing Apparatus for the Determination of Forming Limit under Hot Stamping Conditions

The hot stamping and cold die quenching process is increasingly used to form complex shaped structural components of sheet metals. Conventional experimental approaches, such as out-of-plane and in-plane tests, are not applicable to the determination of forming limits when heating and rapid cooling processes are introduced prior to forming for tests conducted under hot stamping conditions. A novel in-plane biaxial testing system was designed and used for the determination of forming limits of sheet metals at various strain paths, temperatures, and strain rates after heating and cooling processes in a resistance heating uniaxial testing machine. The core part of the biaxial testing system is a biaxial apparatus, which transfers a uniaxial force provided by the uniaxial testing machine to a biaxial force. One type of cruciform specimen was designed and verified for the formability test of aluminum alloy 6082 using the proposed biaxial testing system. The digital image correlation (DIC) system with a high-speed camera was used for taking strain measurements of a specimen during a deformation. The aim of proposing this biaxial testing system is to enable the forming limits of an alloy to be determined at various temperatures and strain rates under hot stamping conditions.

This protocol proposes a novel biaxial testing system used on a resistance heating uniaxial tensile test machine in order to determine the forming limit diagram (FLD) of sheet metals under hot stamping conditions.

Un nouvel appareil d&#39;essai biaxiale pour la détermination de la limite de formage à chaud sous conditions Stamping

The hot stamping and cold die quenching process is increasingly used to form complex shaped structural components of sheet metals. Conventional ...

Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets

In liquid crystal (LC) physical chemistry, molecules near the surface play a great role in controlling bulk orientation. Thus far, mainly to achieve desired molecular orientation states in LC displays, the "static" surface property of LCs, so-called surface anchoring, has been intensively studied. As a rule of thumb, once the initial orientation of LCs is "locked" by specific surface treatments, such as rubbing or treatment with a specific alignment layer, it hardly changes with temperature. Here, we present a system exhibiting an orientational transition upon temperature variation, which conflicts with the consensus. Right on the transition, the bulk LC molecules experience the orientational rotation, with 90&#176; between the planar (P) orientation at high temperatures and the vertical (V) orientation at low temperatures in the first-order transitional manner. We have tracked thermodynamic surface anchoring behavior by means of polarizing optical microscopy (POM), dielectric spectroscopy (DS), high-resolution differential scanning calorimetry (HR-DSC), and grazing incidence X-ray diffraction (GI-XRD) and reached a plausible physical explanation: that the transition is triggered by a growth of surface wetting sheets, which impose the V orientation locally against the P orientation in the bulk. This landscape would provide a general link explaining how the equilibrium bulk orientation is affected by surface-localized orientation in many LC systems. In our characterization, POM and DS are advantageous by offering information on the spatial distribution of the orientation of LC molecules. HR-DSC gives information about the precise thermodynamic information on transitions, which cannot be addressed by conventional DSC instruments due to limited resolution. GI-XRD provides information on surface-specific molecular orientation and short-range orderings. The goal of this paper is to present a protocol for preparing a sample that exhibits the transition and to demonstrate how the thermodynamic structural variation, both in the bulk and on surfaces, can be analyzed through the abovementioned methods.

Here, we present a protocol to trigger an orientational transition of a liquid crystal in response to temperature. Methodologies are described for preparing a sample in order to observe the transition and the detailed transitional evolution.

Transition orientale dans un cristal liquide déclenché par la croissance thermodynamique des feuilles de mouillage interfaciales

In liquid crystal (LC) physical chemistry, molecules near the surface play a great role in controlling bulk orientation. Thus far, mainly to achieve ...

All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics

The miniaturization of semiconductor devices to scales where small numbers of dopants can control device properties requires the development of new techniques capable of characterizing their dynamics. Investigating single dopants requires sub-nanometer spatial resolution, which motivates the use of scanning tunneling microscopy (STM). However, conventional STM is limited to millisecond temporal resolution. Several methods have been developed to overcome this shortcoming, including all-electronic time-resolved STM, which is used in this study to examine dopant dynamics in silicon with nanosecond resolution. The methods presented here are widely accessible and allow for local measurement of a wide variety of dynamics at the atomic scale. A novel time-resolved scanning tunneling spectroscopy technique is presented and used to efficiently search for dynamics.

We demonstrate an all-electronic method to observe nanosecond-resolved charge dynamics of dopant atoms in silicon with a scanning tunneling microscope.

Entièrement électronique résolue en nanosecondes Tunneling microscope à balayage : Faciliter l’Investigation de la dynamique de Charge unique de Dopant

The miniaturization of semiconductor devices to scales where small numbers of dopants can control device properties requires the development of new ...

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape method or individual WS2 nanotubes by dispersing the suspension of WS2 nanotubes. The selected samples have been fabricated into devices by the use of the electron beam lithography and electrolyte is put on the devices. We have characterized the electronic properties of the devices under applying the gate voltage. In the small gate voltage region, ions in the electrolyte are accumulated on the surface of the samples which leads to the large electric potential drop and resultant electrostatic carrier doping at the interface. Ambipolar transfer curve has been observed in this electrostatic doping region. When the gate voltage is further increased, we met another drastic increase of source-drain current which implies that ions are intercalated into layers of WS2 and electrochemical carrier doping is realized. In such electrochemical doping region, superconductivity has been observed. The focused technique provides a powerful strategy for achieving the electric-filed-induced quantum phase transition.

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

Here, we present a protocol to control the carrier number in solids by using the electrolyte.

Contrôle de champ électrique des États électroniques dans WS2 nanodispositifs par électrolyte Gate

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape ...