Name: fabrication of magnetic nanostructures on silicon nitride membranes for magnetic vortex studies using transmission microscopy techniques
Uploaded: 2018-07-02T14:00:00.000+00:00
Duration: 6 min 27 s
Description: Watch this Scientific Journal Video about Fabrication of Magnetic Nanostructures on Silicon Nitride Membranes for Magnetic Vortex Studies Using Transmission Microscopy Techniques at JoVE.com

מחקר זה ייצורם נתמך כלכלית על ידי הסוכנות מענק של צ'כיה (פרוייקט מס 15-34632L) ועל ידי ננו CEITEC + הפרויקט, מזהה CZ.02.1.01/0.0/0.0/16 013/0001728. הזיוף דגימה ומדידה ז בוצעו בהתשתית למחקר ננו CEITEC (מזהה LM2015041, MEYS CR, 2016-2019). מינה Dhankhar נתמכה על ידי מלגה כישרון ברנו Ph.d....

<ol>
	<li>Hubert, A., Sch&#228;fer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Magnetic Domains. The Analysis of Magnetic Microstructures. , (1998).</li><li>Cowburn, R. P., Koltsov, D. K., Adeyeye, A., O, M. E., Welland, M. E., Tricker, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-domain+circular+nanomagnets.">Single-domain circular nanomagnets.</a> Physical Review Letters. 83 (5), 1042-1045 (1999).</li><li>Shinjo, T., Okuno, T., Hassdorf, R., Shigeto, K., Ono, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+vortex+core+observation+in+circular+dots+of+Permalloy.">Magnetic vortex core observation in circular dots of Permalloy.</a> Science. 289 (5481), 930-932 (2000).</li><li>Guslienko, K. Y., Novosad, V., Otani, Y., Shima, H., Fukamichi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetization+reversal+due+to+vortex+nucleation,+displacement,+and+annihilation+in+submicron+ferromagnetic+dot+arrays.">Magnetization reversal due to vortex nucleation, displacement, and annihilation in submicron ferromagnetic dot arrays.</a> Physical Review B. 65, 024414 (2001).</li><li>Guslienko, K. Y., Novosad, V., Otani, Y., Shima, H., Fukamichi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Field+evolution+of+magnetic+vortex+state+in+ferromagnetic+disks.">Field evolution of magnetic vortex state in ferromagnetic disks.</a> Applied Physics Letters. 78 (24), 3848 (2001).</li><li>Schneider, M., Hoffmann, H., Otto, S., Haug, T., Zweck, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stability+of+magnetic+vortices+in+flat+submicron+Permalloy+cylinders.">Stability of magnetic vortices in flat submicron Permalloy cylinders.</a> Journal of Applied Physics. 92 (3), 1466-1472 (2002).</li><li>Van Waeyenberge, B., 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=Magnetic+vortex+core+reversal+by+excitation+with+short+bursts+of+an+alternating+field.">Magnetic vortex core reversal by excitation with short bursts of an alternating field.</a> Nature. 444, 461-464 (2006).</li><li>Kammerer, M., 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=Magnetic+vortex+core+reversal+by+excitation+of+spin+waves.">Magnetic vortex core reversal by excitation of spin waves.</a> Nature Communications. 2, 279 (2011).</li><li>Guslienko, K. Y., Ivanov, B. A., Novosad, V., Otani, Y., Shima, H., Fukamichi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eigenfrequencies+of+vortex+state+excitations+in+magnetic+submicron-size+disks.">Eigenfrequencies of vortex state excitations in magnetic submicron-size disks.</a> Journal of Applied Physics. 91 (10), 813-823 (2002).</li><li>Urb&#225;nek, M., 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=Dynamics+and+efficiency+of+magnetic+vortex+circulation+reversal.">Dynamics and efficiency of magnetic vortex circulation reversal.</a> Physical Review B. 91, 094415 (2015).</li><li>Uhl&#237;&#345;, V., 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=Dynamics+switching+of+the+spin+circulation+in+tapered+magnetic+nanodisks.">Dynamics switching of the spin circulation in tapered magnetic nanodisks.</a> Nature Nanotechnology. 8 (5), 341-346 (2013).</li><li>Jung, H., 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=Logic+operations+based+on+magnetic-vortex-state+networks.">Logic operations based on magnetic-vortex-state networks.</a> ACS Nano. 6 (5), 3712-3717 (2012).</li><li>Hasegawa, N., Sugimoto, S., Fujimori, H., Kondou, K., Niimi, Y., Otani, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+mode+excitation+in+three-chained+magnetic+vortices.">Selective mode excitation in three-chained magnetic vortices.</a> Applied Physics Express. 8 (6), 063005 (2015).</li><li>Wintz, S., 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=Magnetic+vortex+cores+as+tunable+spin-wave+emitters.">Magnetic vortex cores as tunable spin-wave emitters.</a> Nature Nanotechnology. 11, 948-953 (2016).</li><li>Hopster, H., Oepen, H. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Magnetic Microscopy of Nanostructures. , (2005).</li><li>Fischer, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+imaging+with+polarized+soft+x-rays.">Magnetic imaging with polarized soft x-rays.</a> Journal of Physics D: Applied Physics. 50 (31), 313002 (2017).</li><li>Vanatka, M., 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=Magnetic+vortex+nucleation+modes+in+static+magnetic+fields.">Magnetic vortex nucleation modes in static magnetic fields.</a> AIP Advances. 7 (10), 105103 (2017).</li><li>Constancias, C., Landis, S., Manakli, S., Martin, L., Pain, L., Rio, D., Landis, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electron+beam+lithography.">Electron beam lithography.</a> Lithography. , (2013).</li><li>Williams, D. B., Carter, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Transmission Electron Microscopy. A Textbook for Materials Science. , (2009).</li><li>Seshan, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook of Thin-film Deposition Processes and Techniques. , (2002).</li></ol>

המחברים אין לחשוף.

הראו הזיוף של דגימות עבור microscopies מגנטי ז ו- MTXM. דגימות אלה צריך להיות מפוברק על ממברנות חטא דק כך האלקטרונים, במקרה של פריט, צילומי הרנטגן רך, במקרה MTXM, יכול לחדור דרך הדגימות. יכול להיות מפוברק דגימות אלה על-ידי ליתוגרפיה להתנגד חיובי 1) או 2) ליתוגרפיה שלילי להתנגד.
השתמשנו בטכניקה ליתוגרפיה להתנגד חיובי כי היא דורשת הכנת המדגם פחות, פחות צעדים פבריקציה נוספת, מאפשר עיבוד קל יותר. זה גם מאפשר החוקר להשתמש באפקט צל, שאותו היינו עבור הפקד צורה מדויקת דיסק (הצרה של צד אחד של הדיסק). צורה זו נעשה שימוש כדי לשלוט מחזור מערבולות מגנטיות במהלך התגרענות10,11.
החיסרון של שיטה זו הוא ההליך ההמראה מסובך כי החומר סרט דק לפעמים הופקד על הקצה להתנגד, ואז לא ניתן להסיר על ידי ההמראה. פתרנו בעיה זו על-ידי שימוש שכבה כפולה להתנגד. זה קצת מגביל את הרזולוציה (כ-20 ננומטר) של תהליך lithographical אך נותר מספיק לצורך הדמיה מגנטית.
טכניקת הדפס אבן שלילי להתנגד מציעה רזולוציה גבוהה יותר מבנים עם רזולוציה עד 7 nm יכול להיכתב לתוך להתנגד. החומר ואז חרוטה משם על-ידי איכול רטוב או על ידי יון לשגר תחריט. הבעיה עם שיטה זו היא להתנגד קשה להסיר לאחר החריטה. בנוכחות חמצן נפוץ פלזמה להתנגד אחר אינה אפשרית במקרה של מבנים permalloy דק, כפי מתחמצנים בקלות רבה. עובדה זו, יחד עם הצורך להשתמש בטכניקה צל, מיטיבה את תהליך חיובי ליתוגרפיה אשר שימשה במהלך עבודה זו.
השתמשנו בדגימות שהוכנו על ידי בשיטות המתוארות במאמר זה עבור הצפיה הדינמיקה של מערבולות מגנטיות במהלך סירקולציה המעבר על-ידי10,MTXM11 , התצפית של המדינות השונות התגרענות17 . זה ניתן להרחיב סוגים נוספים של ניסויים הדורשים מבנים lithographically מוכן על הממברנות.

המגנטיות של nanostructures נחקרה באופן אינטנסיבי בשני העשורים האחרונים בעקבות מגמות טכנולוגיות לקראת המזעור. כל הממדים לרוחב של המבנים הופכות לקטנות יותר, קטן יותר, תכונות מגנטיות של מבנים פרומגנטי ולהתחיל להיות נשלטת על ידי הצורה הגיאומטרית מבנה בנוסף לתכונות של חומר מגנטי. ההתנהגות של רכיבים מגנטיים שונים של חומרי תפזורת כדי מזערים נצפה פרטים (למשל, על ידי הובר בישיבתו)1. אחת הדוגמאות הידועה ביותר של מצב הקרקע מגנוט לא טריוויאלי הוא מגנטי מבנים מגנוט של מערבולות-קרלינג, המתרחשים מיקרון, כחיוניים-בגודל דיסקים מגנטי דק ומצולעים. מגנוט כאן כרוך סביב בתוך המטוס סביב out-של-plane מערבולת core2,3. היפוך מגנוט של מערבולות מגנטיות נחקרה בהרחבה סטטי4,5,6 והן דינמי7,-8,-9,-10 משטרים. היישומים האפשריים של מערבולות מגנטיות הם, למשל, זיכרון רב יותר תאים11, מעגלים לוגיים12, מכשירי תדר רדיו13או פולטים גלי ספין-14.
כדי בתמונה מערבולת מגנטי במיוחד ליבת מערבולת, הרזולוציה המרחבית של הטכניקה מיקרוסקופ צריך להיות קרוב ככל האפשר כדי היסוד פיסיקליות מגנטי (להלן 10 ננומטר). לורנץ הילוכים מיקרוסקופ אלקטרונים15 (ז) ו תמסורת מגנטית רנטגן מיקרוסקופ16 (MTXM) הם מועמדים אידיאליים עבור ההדמיה של מערבולות מגנטיות כפי שהם מציעים רזולוציה מרחבית גבוהה וגם MTXM מציע גבוה טמפורלית רזולוציה ללימודי dynamics מגנוט. החיסרון של טכניקות אלה הוא הכנת הדוגמא מסובך, וזה הנושא של העיתון שהוצגו.
התהליכים שהוצגו כאן להסביר את הזיוף של דגימות המשמש הדמיה מגנטית מערבולות TEM17 ו- MTXM10,11. בשתי הטכניקות הם אופי השידור, בגלל זה, זה הכרחי כדי לפברק את המבנים על קרום דק. הקרומים עשויים בדרך כלל מ סיליקון ניטריד וטווחים שלהם עובי עשרות ננומטר כמה מאות ננומטר. כל השיטות האלה שני דורשת של הגיאומטריה מסגרת תמיכה שונים. במקרה של MTXM, המסגרת נמצאת 5 x 5 מ מ2 , החלון גדול, 2 x 2 מ מ2. במקרה של TEM, הגיאומטריה מסגרת הוא מעגל של 3 מ מ קוטר עם גודל החלון תלוי הניסוי, בדרך כלל 250 x 250 מיקרומטר2. הממברנות להביא אתגרים נוספים של טיפול מדגם קשה יותר עם הסיכון של שבירת החלונות במהלך כל התהליכים ליתוגרפיה.
הזיוף של דגימות יכול להיעשות על ידי חיוביות ושליליות להתנגד טכניקות הדפס אבן18. התהליך ליתוגרפיה להתנגד חיובי משתמש להתנגד חיובי; המבנה הכימי של השינויים להתנגד על הקרנה, החלק החשוף יהפוך מסיס היזם כימי. באזור החשוף ישטוף בעוד אזור שלא נחשפו יישאר על המצע. במקרה של תהליך ליתוגרפיה להתנגד שלילי, ההקרנות מתקשה להתנגד את, באזור החשוף יישאר על המצע בעוד אזור שלא נחשפו ישטוף במפתח כימי. ניתן להשתמש בשתי הטכניקות הזיוף של הדגימות, אבל אנחנו מעדיפים ליתוגרפיה להתנגד חיובי כי זה דורש פחות שלבים פבריקציה נוספת בהשוואה השלילי להתנגד טכניקת הדפס אבן. זה גם הרבה יותר קל לטפל, מהירה, לעיתים קרובות מספק תוצאות טובות יותר.

<table><tbody><tr><td>SiN Membrane - TEM</td><td>Silson</td><td>SiRN-TEM-200-0.25-500</td><td>TEM membrane</td></tr><tr><td>SiN Membrane - MTXM</td><td>Silson</td><td>SiRN-5.0-200-3.0-200</td><td>MTXM membrane</td></tr><tr><td>3D adapter for spin coating</td><td></td><td></td><td>The model of the adapter for 3D printing can be downloaded at: https://www.thingiverse.com/thing:2808368</td></tr><tr><td>PMMA 950k electron beam resist</td><td>Allresist</td><td>AR-P 679.04</td><td>used for TEM sample</td></tr><tr><td>Electron beam resist developer</td><td>Allresist</td><td>AR 600-56</td><td>used for TEM sample</td></tr><tr><td>High-contrast electron beam resist</td><td>Allresist</td><td>AR-P 6200.13</td><td>used for the waveguide on the MTXM sample</td></tr><tr><td>High-contrast electron beam resist developer</td><td>Allresist</td><td>AR-600-546</td><td>used for the waveguide on the MTXM sample</td></tr><tr><td>Tetrakis(dimethylamido)titanium(IV)</td><td>Sigma Aldrich</td><td>669008 Aldrich&amp;nbsp;</td><td>used for TiO2 thin film deposition by ALD&amp;nbsp;</td></tr><tr><td>Electron beam resist for nanometer lithography</td><td>Allresist</td><td>AR-P 617.02</td><td>used as the bottom layer of bilayer resist for easier lift-off procedure</td></tr><tr><td>PMMA 950k electron beam resist</td><td>Allresist</td><td>AR-P 679.04</td><td>used as the top layer of bilayer resist for easier lift-off procedure</td></tr><tr><td>Electron beam resist developer</td><td>Allresist</td><td>AR 600-56</td><td>used for development of the disks on waveguide</td></tr><tr><td>Permalloy pellets</td><td>Kurt J Lesker</td><td>EVMPERMQXQ-D</td><td>used for the deposition of the magnetic layers</td></tr><tr><td>Titanium pellets</td><td>Kurt J Lesker</td><td>EVMTI45QXQD</td><td>used as adhesive layer for the gold waveguide</td></tr><tr><td>Gold pellets</td><td>Kurt J Lesker</td><td>EVMAUXX40G</td><td>used for the deposition of the waveguide</td></tr></tbody></table>

fabrication of magnetic nanostructures on silicon nitride membranes for magnetic vortex studies using transmission microscopy techniques

Microscopies מגנטי אלקטרונים ורנטגן לאפשר הדמיה מגנטית ברזולוציה גבוהה עד עשרות ננומטר. עם זאת, הדגימות צריכים להיות מוכנים על קרום שקוף אשר הם שבירים מאוד קשה לתמרן. אנו מציגים תהליכים על הזיוף של דגימות עם מיקרו מגנטי, nanostructures עם תצורות ספין ויוצרים מתאים במיקרוסקופ אלקטרונים הילוכים לורנץ, תמסורת מגנטית רנטגן מיקרוסקופ מחקרים מגנטי מערבולות. הדגימות הינן מוכנות על ממברנות הסיליקון ניטריד ואת הזיוף מורכב ספין ציפוי, UV, קרינה לליטוגרפיה, פיתוח כימי להתנגד, אידוי חומר מגנטי ואחריו תהליך ההמראה ויוצרים מבנים מגנטי הסופי. הדגימות במיקרוסקופ אלקטרונים הילוכים לורנץ מורכב מגנטי nanodiscs מוכן בשלב ליתוגרפיה יחיד. הדגימות עבור מיקרוסקופ שידור רנטגן מגנטיים משמשים לניסויים דינאמיים זמן לפתור מגנוט, nanodiscs מגנטי מוצבים גלבו המשמש הדור של השדה המגנטי הדיר פולסים על-ידי העברת חשמלי זרם דרך גלבו. גלבו נוצר בשלב הדפס אבן נוספת.

איור 1 מציג את הצילומים של חטא מסגרות, ממברנות המשמש את microscopies MTXM, ז. איור 2 מציג את העיצוב של המתאמים מודפס 3D כדי להחזיק את TEM ממברנה מהציר במהלך תהליך ציפוי ספין. איור 3 מראה את השלבים השונים של הכנת הדוגמא ז (לאחר פיתוח להתנגד ואחרי ההליך ההמראה) ואת התמונה הסופית (פירושונים) ז. איור 4 מציג את התרשימים? של השלבים הכנה הזיוף של הדיסקים, גלבו את קרום חטא לניסויים זמן לפתור MTXM. איור 5 מראה את הדגימה MTXM הסופי המכיל את הדיסקים מונחת גלבו.

Watch this Scientific Journal Video about Fabrication of Magnetic Nanostructures on Silicon Nitride Membranes for Magnetic Vortex Studies Using Transmission Microscopy Techniques at JoVE.com

Fabrication of Magnetic Nanostructures on Silicon Nitride Membranes for Magnetic Vortex Studies Using Transmission Microscopy Techniques

פרוטוקול להרכבת מיקרו מגנטי - ו nanostructures עם תצורות ספין ויוצרים מתאים במיקרוסקופ אלקטרונים הילוכים (TEM) ולימודי מיקרוסקופ (MTXM) רנטגן תמסורת מגנטית מגנטי מערבולות מוצג.

ייצור של Nanostructures מגנטית על ממברנות הסיליקון ניטריד ללימודי מערבולת מגנטי באמצעות טכניקות במיקרוסקופ שידור

Electron and x-ray magnetic microscopies allow for high-resolution magnetic imaging down to tens of nanometers. However, the samples need to be prepared ...

fabrication-magnetic-nanostructures-on-silicon-nitride-membranes-for

Research

JoVE Journal

Engineering

8.0K Views.  Brno University of Technology. פרוטוקול להרכבת מיקרו מגנטי - ו nanostructures עם תצורות ספין ויוצרים מתאים במיקרוסקופ אלקטרונים הילוכים (TEM) ולימודי מיקרוסקופ (MTXM) רנטגן תמסורת מגנטית מגנטי מערבולות מוצג.

Video: Fabrication of Magnetic Nanostructures on Silicon Nitride Membranes for Magnetic Vortex Studies Using Transmission Microscopy Techniques

Fabricating Nanogaps by Nanoskiving

There are several methods of fabricating nanogaps with controlled spacings, but the precise control over the sub-nanometer spacing between two electrodes-and generating them in practical quantities-is still challenging. The preparation of nanogap electrodes using nanoskiving, which is a form of edge lithography, is a fast, simple and powerful technique. This method is an entirely mechanical process which does not include any photo- or electron-beam lithographic steps and does not require any special equipment or infrastructure such as clean rooms. Nanoskiving is used to fabricate electrically addressable nanogaps with control over all three dimensions; the smallest dimension of these structures is defined by the thickness of the sacrificial layer (Al or Ag) or self-assembled monolayers. These wires can be manually positioned by transporting them on drops of water and are directly electrically-addressable; no further lithography is required to connect them to an electrometer.

The fabrication of electrically addressable, high-aspect-ratio (> 1000:1) metal nanowires separated by gaps of single nanometers using either sacrificial layers of aluminum and silver or self-assembled monolayers as templates is described. These nanogap structures are fabricated without a clean room or any photo- or electron-beam lithographic processes by a form of edge lithography known as nanoskiving.

בודה Nanogaps ידי Nanoskiving

There are several methods of fabricating nanogaps with controlled spacings, but the precise control over the sub-nanometer spacing between two ...

Chemistry

Fabrication of Uniform Nanoscale Cavities via Silicon Direct Wafer Bonding

Measurements of the heat capacity and superfluid fraction of confined 4He have been performed near the lambda transition using lithographically patterned and bonded silicon wafers. Unlike confinements in porous materials often used for these types of experiments3, bonded wafers provide predesigned uniform spaces for confinement. The geometry of each cell is well known, which removes a large source of ambiguity in the interpretation of data.
Exceptionally flat, 5 cm diameter, 375 &#181;m thick Si wafers with about 1 &#181;m variation over the entire wafer can be obtained commercially (from Semiconductor Processing Company, for example). Thermal oxide is grown on the wafers to define the confinement dimension in the z-direction. A pattern is then etched in the oxide using lithographic techniques so as to create a desired enclosure upon bonding. A hole is drilled in one of the wafers (the top) to allow for the introduction of the liquid to be measured. The wafers are cleaned2 in RCA solutions and then put in a microclean chamber where they are rinsed with deionized water4. The wafers are bonded at RT and then annealed at ~1,100 &#176;C. This forms a strong and permanent bond. This process can be used to make uniform enclosures for measuring thermal and hydrodynamic properties of confined liquids from the nanometer to the micrometer scale.

A method for permanently bonding two silicon wafers so as to realize a uniform enclosure is described. This includes wafer preparation, cleaning, RT bonding, and annealing processes. The resulting bonded wafers (cells) have uniformity of enclosure ~1%1,2. The resulting geometry allows for measurements of confined liquids and gasses.

ייצור חללים ננומטריים אחידים באמצעות מליטה וופל ישיר סיליקון

Measurements of the heat capacity and superfluid fraction of confined 4He have been performed near the lambda transition using lithographically patterned ...

Fabrication and Operation of a Nano-Optical Conveyor Belt

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological and physical sciences over the past few decades. The progress made in this field invites further study of even smaller systems and at a larger scale, with tools that could be distributed more easily and made more widely available. Unfortunately, the fundamental laws of diffraction limit the minimum size of the focal spot of a laser beam, which makes particles smaller than a half-wavelength in diameter hard to trap and generally prevents an operator from discriminating between particles which are closer together than one half-wavelength. This precludes the optical manipulation of many closely-spaced nanoparticles and&#160;limits the&#160;resolution of optical-mechanical systems. Furthermore, manipulation using focused beams requires beam-forming or steering optics, which can be very bulky and expensive. To address these limitations in the system scalability of conventional optical trapping our lab has devised an alternative technique which utilizes near-field optics to move particles across a chip. Instead of focusing laser beams in the far-field, the optical near field of plasmonic resonators produces the necessary local optical intensity enhancement to overcome the restrictions of diffraction and manipulate particles at higher resolution. Closely-spaced resonators produce strong optical traps which can be addressed to mediate the hand-off of particles from one to the next in a conveyor-belt-like fashion. Here, we describe how to design and produce a conveyor belt using a gold surface patterned with plasmonic C-shaped resonators and how to operate it with polarized laser light to achieve super-resolution nanoparticle manipulation and transport. The nano-optical conveyor belt chip can be produced using lithography techniques and easily packaged and distributed.

The scalability and resolution of conventional optical manipulation techniques are limited by diffraction. We circumvent the diffraction limit and describe a method of optically transporting nanoparticles across a chip using a gold surface patterned with a path of closely spaced C-shaped plasmonic resonators.

ייצור ותפעול של מסוע ננו-אופטי

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological ...

Atomically Traceable Nanostructure Fabrication

Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure.

We report a protocol for combining the atomic metrology of the Scanning Tunneling Microscope for surface patterning with selective Atomic Layer Deposition and Reactive Ion Etching. Using a robust process involving numerous atmospheric exposures and transport, 3D nanostructures with atomic metrology are fabricated.

ייצור ננו-מבנה אטומי למעקב

Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process ...

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T.

We describe the methodology of mechanical exfoliation and deposition of flakes of novel materials with micron-sized dimensions onto substrate, fabrication of experimental device structures for transport experimentation, and the magnetotransport measurement in a dry helium close-cycle cryostat at temperatures down to 0.300 K and magnetic fields up to 12 T.

שיטות ניסיוניות מתקדמות לטמפרטורה נמוכה Magnetotransport מדידה של חומרים חדשים

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film ...

Scanning SQUID Study of Vortex Manipulation by Local Contact

Local, deterministic manipulation of individual vortices in type 2 superconductors is challenging. The ability to control the position of individual vortices is necessary in order to study how vortices interact with each other, with the lattice, and with other magnetic objects. Here, we present a protocol for vortex manipulation in thin superconducting films by local contact, without applying current or magnetic field. Vortices are imaged using a scanning superconducting quantum interference device (SQUID), and vertical stress is applied to the sample by pushing the tip of a silicon chip into the sample, using a piezoelectric element. Vortices are moved by tapping the sample or sweeping it with the silicon tip. Our method allows for effective manipulation of individual vortices, without damaging the film or affecting its topography. We demonstrate how vortices were relocated to distances of up to 0.8 mm. The vortices remained stable at their new location up to five days. With this method, we can control vortices and move them to form complex configurations. This technique for vortex manipulation could also be implemented in applications such as vortex based logic devices.

We present a protocol for manipulation of individual vortices in thin superconducting films, using local mechanical contact. The method does not include applying current, magnetic field or additional fabrication steps.

סריקת לימוד SQUID של מניפולציה וורטקס ידי לתקשר מקומי

Local, deterministic manipulation of individual vortices in type 2 superconductors is challenging. The ability to control the position of individual ...

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and forging. Adoption of this technique is proceeding despite disagreement concerning the underlying mechanism responsible for EAD. The experimental procedure described herein enables a more explicit study compared to previous EAD research by removing thermal effects, which are responsible for disagreement in interpreting previous EAD results. Furthermore, as the procedure described here enables EAD observation in situ and in real time in a transmission electron microscope (TEM), it is superior to existing post-mortem methods that observe EAD effects post-test. Test samples consist of a single crystal copper (SCC) foil having a free-standing tensile test section of nanoscale thickness, fabricated using a combination of laser and ion beam milling. The SCC is mounted to an etched silicon base that provides mechanical support and electrical isolation while serving as a heat sink. Using this geometry, even at high current density (~3,500 A/mm2), the test section experiences a negligible temperature increase (&#60;0.02 &#176;C), thus eliminating Joule heating effects. Monitoring material deformation and identifying the corresponding changes to microstructures, e.g. dislocations, are accomplished by acquiring and analyzing a series of TEM images. Our sample preparation and in situ experiment procedures are robust and versatile as they can be readily utilized to test materials with different microstructures, e.g., single and polycrystalline copper.

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Isolating electrical and thermal effects on electrically assisted deformation (EAD) is very difficult using macroscopic samples. Metallic sample micro- and nanostructures together with a custom test procedure have been developed to evaluate the impact of applied current on the formation without joule heating and evolution of dislocations on these samples.

שיטה חדשה עבור<em&gt; באתרו</em&gt; אפיון אלקטרומכני של דגימות ננומטריות

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and ...

Iron Nanowire Fabrication by Nano-Porous Anodized Aluminum and its Characterization

Magnetic nanowires possess unique properties that have attracted the interest of different fields of research, including basic physics, biomedicine, and data storage. We demonstrate a fabrication method for iron (Fe) nanowires&#160;via electrochemical deposition into anodic&#160;alumina oxide (AAO) templates. The templates are fabricated by anodization of aluminum (Al) discs, and the pore length and diameter are controlled by changing the anodizing conditions. Pores with an average diameter of around 120 nm are created using oxalic acid as the electrolyte. Using this method, cylindrical nanowires are synthesized, which are released by dissolving the alumina using a selective chemical etchant.

In this work, we describe a&#160;protocol to fabricate iron nanowires, including the formation of the porous alumina membrane that is used as the template, electrodeposition into templates using electrolyte solution, and the release of the nanowires into the solution.

ברזל יצוק בייצור ננו-נקבובי אלומיניום ואיפיון

Magnetic nanowires possess unique properties that have attracted the interest of different fields of research, including basic physics, biomedicine, and ...

Magnetic Field Mapping using Off-Axis Electron Holography in the Transmission Electron Microscope

Off-axis electron holography is a powerful technique that involves the formation of an interference pattern in a transmission electron microscope (TEM) by overlapping two parts of an electron wave, one of which has passed through a region of interest on a specimen and the other is a reference wave. The resulting off-axis electron hologram can be analyzed digitally to recover the phase difference between the two parts of the electron wave, which can then be interpreted to provide quantitative information about local variations in electrostatic potential and magnetic induction within and around the specimen. Off-axis electron holograms can be recorded while a specimen is subjected to external stimuli such as elevated or reduced temperature, voltage, or light. The protocol that is presented here describes the practical steps that are required to record, analyze, and interpret off-axis electron holograms, with a primary focus on the measurement of magnetic fields within and around nanoscale materials and devices. Presented here are the steps involved in the recording, analysis, and processing of off-axis electron holograms, as well as the reconstruction and interpretation of phase images and visualization of the results. Also discussed are the need for optimization of the specimen geometry, the electron optical configuration of the microscope, and the electron hologram acquisition parameters, as well as the need for the use of information from multiple holograms to extract the desired magnetic contributions from the recorded signal. The steps are illustrated through a study of specimens of B20-type FeGe, which contain magnetic skyrmions and were prepared with focused ion beams (FIBs). Prospects for the future development of the technique are discussed.

Guidelines are presented for recording and interpreting off-axis electron holograms to provide quantitative images of magnetic fields in nanoscale materials and devices in the transmission electron microscope.

Off-axis electron holography is a powerful technique that involves the formation of an interference pattern in a transmission electron microscope (TEM) by ...

Optimizing Magnetic Force Microscopy Resolution and Sensitivity to Visualize Nanoscale Magnetic Domains

Magnetic force microscopy (MFM) enables mapping local magnetic fields across a sample surface with nanoscale resolution. To perform MFM, an atomic force microscopy (AFM) probe whose tip has been magnetized vertically (i.e., perpendicular to the probe cantilever) is oscillated at a fixed height above the sample surface. The resultant shifts in the oscillation phase or frequency, which are proportional to the magnitude and sign of the vertical magnetic force gradient at each pixel location, are then tracked and mapped. Although the spatial resolution and sensitivity of the technique increases with decreasing lift height above the surface, this seemingly straightforward path to improved MFM images is complicated by considerations such as minimizing topographical artifacts due to shorter range van der Waals forces, increasing the oscillation amplitude to further improve sensitivity, and the presence of surface contaminants (in particular water due to humidity under ambient conditions). In addition, due to the orientation of the probe's magnetic dipole moment, MFM is intrinsically more sensitive to samples with an out-of-plane magnetization vector. Here, high-resolution topographical and magnetic phase images of single and bicomponent nanomagnet artificial spin-ice (ASI) arrays obtained in an inert (argon) atmosphere glovebox with &lt;0.1 ppm O2 and H2O are reported. Optimization of lift height and drive amplitude for high resolution and sensitivity while simultaneously avoiding the introduction of topographical artifacts is discussed, and detection of the stray magnetic fields emanating from either end of the nanoscale bar magnets (~250 nm long and &lt;100 nm wide) aligned in the plane of the ASI sample surface is shown. Likewise, using the example of a Ni-Mn-Ga magnetic shape memory alloy (MSMA), MFM is demonstrated in an inert atmosphere with magnetic phase sensitivity capable of resolving a series of adjacent magnetic domains each ~200 nm wide.

Magnetic force microscopy (MFM) employs a vertically magnetized atomic force microscopy probe to measure sample topography and local magnetic field strength with nanoscale resolution. Optimizing MFM spatial resolution and sensitivity requires balancing decreasing lift height against increasing drive (oscillation) amplitude, and benefits from operating in an inert atmosphere glovebox.

אופטימיזציה של רזולוציה ורגישות מיקרוסקופית כוח מגנטי כדי להמחיש תחומים מגנטיים בקנה מידה ננומטרי

Magnetic force microscopy (MFM) enables mapping local magnetic fields across a sample surface with nanoscale resolution. To perform MFM, an atomic force ...