Name: advanced experimental methods for low-temperature magnetotransport measurement of novel materials
Uploaded: 2016-01-21T14:00:00.000+00:00
Duration: 10 min 36 s
Description: Watch this Scientific Journal Video about Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials at JoVE.com

This work is supported by the National Institute of Standards and Technology of the United States Department of Commerce.

<ol>
	<li>Doty, F. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Properties+of+CdZnTe+crystals+grown+by+a+high+pressure+Bridgman+method.">Properties of CdZnTe crystals grown by a high pressure Bridgman method.</a> Journal of Vacuum Science &amp; Technology B. 10 (4), 1418-1422 (1992).</li><li>Ikesue, A., Kinoshita, T., Kamata, K., Yoshida, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+and+optical+properties+of+high-performance+polycrystalline+Nd-YAG+Ceramics+for+Solid-State+Lasers.">Fabrication and optical properties of high-performance polycrystalline Nd-YAG Ceramics for Solid-State Lasers.</a> Journal of the American Ceramic Society. 78 (4), 1033-1040 (1995).</li><li>Elwell, D., Scheel, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Crystal Growth From High-Temperature Solutions. , (2011).</li><li>Doty, F. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Properties+of+CdZnTe+crystals+grown+by+a+high+pressure+Bridgman+method.">Properties of CdZnTe crystals grown by a high pressure Bridgman method.</a> Journal of Vacuum Science &amp; Technology B. 10 (4), 1418-1422 (1992).</li><li>Ikesue, A., Kinoshita, T., Kamata, K., Yoshida, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+and+optical+properties+of+high-performance+polycrystalline+Nd-YAG+Ceramics+for+Solid-State+Lasers.">Fabrication and optical properties of high-performance polycrystalline Nd-YAG Ceramics for Solid-State Lasers.</a> Journal of the American Ceramic Society. 78 (4), 1033-1040 (1995).</li><li>Elwell, D., Scheel, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Crystal Growth From High-Temperature Solutions. , (2011).</li><li>Therese, G. H. A., Kamath, P. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemical+Synthesis+of+Metal+Oxides+and+Hydroxides.">Electrochemical Synthesis of Metal Oxides and Hydroxides.</a> Chemistry of Materials. 12, 1195-1294 (2000).</li><li>Capper, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bulk+Crystal+Growth+-+Methods+and+Materials.">Bulk Crystal Growth - Methods and Materials.</a> Handbook of Electronic and Photonic Materials. , 231-254 (2007).</li><li>Seiler, D. G., Becker, W. M., Roth, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inversion-Asymmetry+Splitting+of+the+Conduction+Band+in+GaSb+from+Shubnikov-de+Haas+Measurements.">Inversion-Asymmetry Splitting of the Conduction Band in GaSb from Shubnikov-de Haas Measurements.</a> Physical Review B. 1, 764-775 (1970).</li><li>Greenblatt, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molybdenum+Oxide+Bronzes+with+Quasi-Low-Dimensional+Properties.">Molybdenum Oxide Bronzes with Quasi-Low-Dimensional Properties.</a> Chemical Reviews. 88, 31-53 (1988).</li><li>Novoselov, K. 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=Two-dimensional+gas+of+massless+Dirac+fermions+in+graphene.">Two-dimensional gas of massless Dirac fermions in graphene.</a> Nature. 438, 197-200 (2005).</li><li>Wang, L., 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=One-Dimensional+Electrical+Contact+to+a+Two-Dimensional+Metal.">One-Dimensional Electrical Contact to a Two-Dimensional Metal.</a> Science. 342, 614-617 (2013).</li><li>Giessibl, F. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+in+Atomic+Force+Microscopy.">Advances in Atomic Force Microscopy.</a> Reviews of Modern Physics. 75, 949-983 (2003).</li><li>Smith, K. C. A., Oatley, C. 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+Scanning+Electron+Microscope+and+its+Fields+of+Applications.">The Scanning Electron Microscope and its Fields of Applications.</a> British Journal of Applied Physics. 6, 391-399 (1955).</li><li>Geim, A. K., Grigorieva, I. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Van+der+Waals+heterostructures.">Van der Waals heterostructures.</a> Nature. 499, 419-425 (2013).</li></ol>

The authors declare no competing financial interests. Commercial materials, instruments and equipment are identified in this paper to specify the experimental procedure as completely as possible. In no case does such identification imply a recommendation or endorsement by the National Institute of Standards.

적절한 구성과 구조를 확인하기 위해 특징으로 고품질의 대량 샘플의 취득 후, 샘플은 1cm 기판의 × 1cm 조각에 샘플 조각을 엑스 폴리 에이 팅에 의해 묘사 된 형상으로 패터닝된다. 그들은 백 게이트의 적용을 허용함으로써 실험적 파라미터 공간을 증가로서 SiO2를 약 300nm의 적용 무겁게 p- 도핑 된 Si로 이루어지는 기판이 바람직하다. 샘플은 충분히 얇아 야 - 미만 10 내지 - 튜닝에 충분한 ...

첨단 전자 기술 재료 플랫폼의 추구는 높은 처리량 재료 합성 및 후속 특성에 대한 방법을 요구한다. 이 추구 관심 신규 물질은 분자 빔 에피 택시 또는 더 복잡한 단결정 박막 형성 기술보다 더 빠른 방식으로 직접 반응 합성 1,2-, 전기 화학적 성장, 4, 및 기타 방법 (5)에 의해 대량으로 제조 할 수있다 화학 증착법. 벌크 크리스탈 샘플의 전송 특성을 측정하는 종래의 방법은 약 1mm X 1mm X 6mm의 치수를 갖는 직육면체 형상의 조각을 절단하고 와이어 홀 바 구성 6 샘플에 이르게 부착하는 것이다. 기존의 벌크 홀바 디바이스의 제조 방법은, 시료의 측정에 대한 전송 측정 가능한 장치를 제조하기에 충분 상기 특정 재료는 도전을 제기. 이있을 수있다원하는 샘플 두께는 단지 몇 개의 단일 층에 하나의 순서, 또는 때문에 생산 결정에도 강력한 광학 현미경에 리드선을 부착 너무 작아 발생할 한 층상 이차원의 스택을 측정하는 것을 목적으로하기 때문에 근 또는 서브 나노 미터 두께의 재료. 첫 번째 범주는 예를 들어 나노 와이어로 구성하고, 산화 몰리브덴의 특정 제제는 7 청동. 두 번째 범주는 그래 핀 (8)과 같은 두 가지 차원 물질의 단일 매우-몇 개의 층으로 이루어져있다, TMDS (MOS 2, WTE 2 등), 및 위상 절연체 (BI 2 SE 3은, 양성애자는 Sb로 1-X 테 (3) X 등). 세 번째 범주는 계층 전송, HBN-그래 핀 HBN 9 특히 중층 스택을 통해 수동 조립하여 두 차원 재료의 각 층을 적층하여 제조 된 헤테로 구조로 구성되어 있습니다. 새로운 전자의 탐색 적 연구lectronic 재료 어려운 샘플들에 측정 장치를 제조하기위한 적절한 방법을 요구한다. 종종, 직접 반응 또는 전기 화학적 성장에 의해 합성 된 새로운 물질의 첫 번째 배치는 마이크론의 크기 순서에 치수가 매우 작은 단결정을 얻을 수 있습니다. 이러한 샘플은 역사적으로 새로운 물질의 높은 처리량 연구 장애물 프리젠 쉽게 운송 장치의 제조를 위해 더 큰 결정을 달성하기 위해 샘플 성장 파라미터의 향상을 필요로 금속 접촉부를 연결하는 거대 어려운 입증. 물질의 신속한 특성화를 가능하게하기 위해, 매우 작은 샘플 장치의 제조 방법은 즉시 예비 일괄 제작 되었기 때문에 신규 한 물질의 특성을 허용하기 위해 고안되었다. 이 방법의 약간의 변화는, 그러한 그라, HBN 및 TMDS 같은 이차원 물질 샘플을 사용하여 박리 된 장치뿐만 아니라 MA의 다층 헤테로 구조의 제조에 적용 할 수있다terials. 장치가 부착 및 상용 초전도 자석, 건조 헬륨 근접주기 그라 이오 스탯 magnetotransport 시스템에 삽입 패키지에 와이어 본딩. 전송 측정은 T. (12)까지 0.300 K 아래로 온도와 자기장에서 촬영

<table><tbody><tr><td>Cryogenic Limited 12 T CFMS</td><td>Cryogen Limited</td><td>CFM-12T-H3- IVTI-25</td><td>Magnetotransport system customized with modulated field magnet (step 4)</td></tr><tr><td>7270 DSP Lock-in amplifier</td><td>Signal Recovery</td><td>7270</td><td>lock-in amplifier for source/drain and voltage measurements (step 4)</td></tr><tr><td>GS200 DC Voltage/Current Source</td><td>Yokogawa</td><td>GS200</td><td>Voltage source for gate voltage application (step 4)</td></tr><tr><td>2636B System Sourcemeter</td><td>Keithley</td><td>2636B</td><td>Sourcemeter for source/drain and voltage measurements</td></tr><tr><td>DWL 2000 Laser Pattern Generator</td><td>Heidelberg Instruments</td><td>DWL 2000</td><td>Generate chrome mask for lithography of substrate location/alignment feature pattern (step 1.3)</td></tr><tr><td>Suss MicroTec MA6/BA6 Contact Aligner</td><td>Suss</td><td>MA6</td><td>Used for the lithography of substrate location/alignment feature pattern (step 1.4.12)</td></tr><tr><td>JEOL Direct Write Electron Beam Lithography System</td><td>JEOL</td><td>JBX 6300-FS&amp;nbsp;</td><td>Perform high-resolution lithography of devices</td></tr><tr><td>Discovery 550 Sputtering System</td><td>Denton Vacuum</td><td>Discovery 550</td><td>Perform SiO&lt;sub&gt;2&lt;/sub&gt; sputtering (step 2.5)</td></tr><tr><td>Infinity 22 Electron Beam Evaporator</td><td>Denton Vacuum</td><td>Infinty 22</td><td>Perform Cr/Au deposition (steps 1.5 and 3.7)</td></tr><tr><td>Unaxis 790 Reactive Ion Etcher</td><td>Unaxis</td><td>Unaxis 790</td><td>Etch sample into Hall bar structure (step 3.4)</td></tr><tr><td>PMMA 495 A4</td><td>MicroChem</td><td>PMMA 495 A4</td><td>Polymer coating/electron beam mask for lithography (step 3.5.1)</td></tr><tr><td>PMMA 950 A4</td><td>MicroChem</td><td>PMMA 950 A4</td><td>Polymer coating/electron beam mask for sample dicing and lithography (steps 1.7.3, 3.3.1, and 3.5.2)</td></tr><tr><td>S1813 positive photoresist</td><td>MicroChem</td><td>S1813 G2</td><td>Positive photoresist (step 1.4.8)</td></tr><tr><td>LOR resist</td><td>MicroChem</td><td>LOR 3A</td><td>Lift off resist (step 1.4.3)</td></tr><tr><td>1:3 MIBK:IPA PMMA developer</td><td>MicroChem</td><td>1:3 MIBK:IPA</td><td>PMMA developer</td></tr><tr><td>MF-321 Developer</td><td>MicroChem</td><td>MF-321</td><td>Novolac positive photoresist-compatible developer solution (step 1.4.15)</td></tr><tr><td>Diglycidiyl ether-terminated polydimethylsiloxane</td><td>Sigma Aldrich</td><td>SA 480282</td><td>For layered material stacking (step 2.6.1)</td></tr><tr><td>Polypropylene carbonate</td><td>Sigma Aldrich</td><td>SA 389021</td><td>For layered material stacking (step 2.6.2)</td></tr></tbody></table>

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.

도 3은 저온 magnetotransport 실험 목적 패터닝 전형적인 홀바 장치를 도시한다. 위 그림의 광학 이미지는 성공적으로 제작 된 그래 핀 / HBN 홀 막대를 보여줍니다; 하부 이미지 랜도 레벨 (LLS)에서 발생 론 도어-Büttiker 에지 상태를 갖는 장치 개략적 인 양자화 홀 저항의 값을 계산하는데 사용될 수있는 전송 메카니즘으로 설명 될 것이다의 실험적 조사를 도시 이 ?...

Watch this Scientific Journal Video about Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials at JoVE.com

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

소설 재료의 저온 Magnetotransport 측정을위한 고급 실험 방법

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.

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

advanced-experimental-methods-for-low-temperature-magnetotransport

Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

10.5K 조회수.  National Institute of Standards and Technology. 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.

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

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

The physical properties of a material are defined by its electronic structure. Electrons in solids are characterized by energy (&omega;) and momentum (k) and the probability to find them in a particular state with given &omega; and k is described by the spectral function A(k, &omega;). This function can be directly measured in an experiment based on the well-known photoelectric effect, for the explanation of which Albert Einstein received the Nobel Prize back in 1921. In the photoelectric effect the light shone on a surface ejects electrons from the material. According to Einstein, energy conservation allows one to determine the energy of an electron inside the sample, provided the energy of the light photon and kinetic energy of the outgoing photoelectron are known. Momentum conservation makes it also possible to estimate k relating it to the momentum of the photoelectron by measuring the angle at which the photoelectron left the surface. The modern version of this technique is called Angle-Resolved Photoemission Spectroscopy (ARPES) and exploits both conservation laws in order to determine the electronic structure, i.e. energy and momentum of electrons inside the solid. In order to resolve the details crucial for understanding the topical problems of condensed matter physics, three quantities need to be minimized: uncertainty* in photon energy, uncertainty in kinetic energy of photoelectrons and temperature of the sample.
In our approach we combine three recent achievements in the field of synchrotron radiation, surface science and cryogenics. We use synchrotron radiation with tunable photon energy contributing an uncertainty of the order of 1 meV, an electron energy analyzer which detects the kinetic energies with a precision of the order of 1 meV and a He3 cryostat which allows us to keep the temperature of the sample below 1 K. We discuss the exemplary results obtained on single crystals of Sr2RuO4 and some other materials. The electronic structure of this material can be determined with an unprecedented clarity.

The overall goal of this method is to determine the low-energy electronic structure of solids at ultra-low temperatures using Angle-Resolved Photoemission Spectroscopy with synchrotron radiation.

울트라 낮은 온도에서 각도 - 해결 Photoemission 분광법

The physical properties of a material are defined by its  electronic structure. Electrons in solids are characterized by energy (&omega;)  and momentum ...

연구

공학

Sputter Growth and Characterization of Metamagnetic B2-ordered FeRh Epilayers

Chemically ordered alloys are useful in a variety of magnetic nanotechnologies. They are most conveniently prepared at an industrial scale using sputtering techniques. Here we describe a method for preparing epitaxial thin films of B2-ordered FeRh by sputter deposition onto single crystal MgO substrates. Deposition at a slow rate onto a heated substrate allows time for the adatoms to both settle into a lattice with a well-defined epitaxial relationship with the substrate and also to find their proper places in the Fe and Rh sublattices of the B2 structure. The structure is conveniently characterized with X-ray reflectometry and diffraction and can be visualised directly using transmission electron micrograph cross-sections. B2-ordered FeRh exhibits an unusual metamagnetic phase transition: the ground state is antiferromagnetic but the alloy transforms into a ferromagnet on heating with a typical transition temperature of about 380 K. This is accompanied by a 1% volume expansion of the unit cell: isotropic in bulk, but laterally clamped in an epilayer. The presence of the antiferromagnetic ground state and the associated first order phase transition is very sensitive to the correct equiatomic stoichiometry and proper B2 ordering, and so is a convenient means to demonstrate the quality of the layers that can be deposited with this approach. We also give some examples of the various techniques by which the change in phase can be detected.

A method to prepare epitaxial layers of ordered alloys by sputtering is described. The B2-ordered FeRh compound is used as an example, as it displays a metamagnetic transition that depends sensitively on the degree of chemical order and the exact composition of the alloy.

Metamagnetic B2-주문 FeRh 에피 층의 스퍼터 성장과 특성

Chemically ordered alloys are useful in a variety of magnetic nanotechnologies. They are most conveniently prepared at an industrial scale using ...

Writing and Low-Temperature Characterization of Oxide Nanostructures

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions. Oxide interfaces exhibit a wide range of properties that can be controlled include conduction, piezoelectric behavior, ferromagnetism, superconductivity and nonlinear optical properties. Recently, methods for controlling these properties at extreme nanoscale dimensions have been discovered and developed. Here are described explicit step-by-step procedures for creating LaAlO3/SrTiO3 nanostructures using a reversible conductive atomic force microscopy technique. The processing steps for creating electrical contacts to the LaAlO3/SrTiO3 interface are first described. Conductive nanostructures are created by applying voltages to a conductive atomic force microscope tip and locally switching the LaAlO3/SrTiO3 interface to a conductive state. A versatile nanolithography toolkit has been developed expressly for the purpose of controlling the atomic force microscope (AFM) tip path and voltage. Then, these nanostructures are placed in a cryostat and transport measurements are performed. The procedures described here should be useful to others wishing to conduct research in oxide nanoelectronics.

Oxide nanostructures provide new opportunities for science and technology. The interfacial conductivity between LaAlO3 and SrTiO3 can be controlled with near-atomic precision using a conductive atomic force microscopy technique. The protocol for creating and measuring conductive nanostructures at LaAlO3/SrTiO3 interfaces is demonstrated.

작성 및 산화물 나노 구조의 저온 특성

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions.  Oxide ...

Chemical Vapor Deposition of an Organic Magnet, Vanadium Tetracyanoethylene

Recent progress in the field of organic materials has yielded devices such as organic light emitting diodes (OLEDs) which have advantages not found in traditional materials, including low cost and mechanical flexibility. In a similar vein, it would be advantageous to expand the use of organics into high frequency electronics and spin-based electronics. This work presents a synthetic process for the growth of thin films of the room temperature organic ferrimagnet, vanadium tetracyanoethylene (V[TCNE]x, x~2) by low temperature chemical vapor deposition (CVD). The thin film is grown at &#60;60 &#176;C, and can accommodate a wide variety of substrates including, but not limited to, silicon, glass, Teflon and flexible substrates. The conformal deposition is conducive to pre-patterned and three-dimensional structures as well. Additionally this technique can yield films with thicknesses ranging from 30 nm to several microns. Recent progress in optimization of film growth creates a film whose qualities, such as higher Curie temperature (600 K), improved magnetic homogeneity, and narrow ferromagnetic resonance line-width (1.5 G) show promise for a variety of applications in spintronics and microwave electronics.

We present the synthesis of the organic-based ferrimagnet vanadium tetracyanoethylene (V[TCNE]x, x~2) via low temperature chemical vapor deposition (CVD). This optimized recipe yields an increase in Curie temperature from 400 K to over 600 K and a dramatic improvement in magnetic resonance properties.

자석의 유기 화학 기상 증착, 바나듐 테트라시

Recent progress in the field of organic materials has yielded devices such as organic light emitting diodes (OLEDs) which have advantages not found in ...

화학

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.

모든 전자 나노초 해결 주사 터널링 현미경: 촉진 단일 불순물 충전 역학 조사

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

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic glasses (MGs). Despite their amorphous nature, the identification of hyperfine interactions unveils faint structural modifications. For this purpose, we have employed two techniques that utilize nuclear resonance among nuclear levels of a stable 57Fe isotope, namely M&#246;ssbauer spectrometry and nuclear forward scattering (NFS) of synchrotron radiation. The effects of heat treatment upon (Fe2.85Co1)77Mo8Cu1B14 MG are discussed using the results of ex situ and in situ experiments, respectively. As both methods are sensitive to hyperfine interactions, information on structural arrangement as well as on magnetic microstructure is readily available. M&#246;ssbauer spectrometry performed ex situ describes how the structural arrangement and magnetic microstructure appears at room temperature after the annealing under certain conditions (temperature, time), and thus this technique inspects steady states. On the other hand, NFS data are recorded in situ during dynamically changing temperature and NFS examines transient states. The use of both techniques provides complementary information. In general, they can be applied to any suitable system in which it is important to know its steady state but also transient states.

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Here, we present a protocol to describe ex situ and in situ investigations of structural transformations in metallic glasses. We employed nuclear-based analytical methods which inspect hyperfine interactions. We demonstrate the applicability of M&#246;ssbauer spectrometry and nuclear forward scattering of synchrotron radiation during temperature-driven experiments.

전 Situ 수사 현장에서 구조 변환 방법: 금속 유리의 결정 화의 경우

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic ...

Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope

The quest to understand correlated electronic systems has pushed the frontiers of experimental measurements toward the development of new experimental techniques and methodologies. Here we use a novel home-built uniaxial-strain device integrated into our variable temperature scanning tunneling microscope that enables us to controllably manipulate in-plane uniaxial strain in samples and probe their electronic response at the atomic scale. Using scanning tunneling microscopy (STM) with spin-polarization techniques, we visualize antiferromagnetic (AFM) domains and their atomic structure in Fe1+yTe samples, the parent compound of iron-based superconductors, and demonstrate how these domains respond to applied uniaxial strain. We observe the bidirectional AFM domains in the unstrained sample, with an average domain size of ~50-150 nm, to transition into a single unidirectional domain under applied uniaxial strain. The findings presented here open a new direction to utilize a valuable tuning parameter in STM, as well as other spectroscopic techniques, both for tuning the electronic properties as for inducing symmetry breaking in quantum material systems.

Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope

Using uniaxial strain combined with spin-polarized scanning tunneling microscopy, we visualize and manipulate the antiferromagnetic domain structure of Fe1+yTe, the parent compound of iron-based superconductors.

단축 긴장 조작 Fe1 +Y테 스핀 편광 스캔 터널링 현미경을 사용 하 여 Antiferromagnetic 도메인의 시각화

The quest to understand correlated electronic systems has pushed the frontiers of experimental measurements toward the development of new experimental ...

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.

자기력 현미경 분해능과 감도를 최적화하여 나노스케일 자기 도메인 시각화

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

Redox-Active MOF의 자기 측정 특성 분석 Solid-State Electrochemistry

Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks

Electrochemical energy storage has been a widely discussed application of redox-active metal-organic frameworks (MOFs) in the past 5 years. Although MOFs show outstanding performance in terms of gravimetric or areal capacitance and cyclic stability, unfortunately their electrochemical mechanisms are not well understood in most cases. Traditional spectroscopic techniques, such as X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS), have only provided vague and qualitative information about valence changes of certain elements, and the mechanisms proposed based on such information are often highly disputable. In this article, we report a series of standardized methods, including the fabrication of solid-state electrochemical cells, electrochemistry measurements, the disassembly of cells, the collection of MOF electrochemical intermediates, and physical measurements of the intermediates under the protection of inert gases. By using these methods for quantitatively clarifying the electronic and spin state evolution within a single electrochemical step of redox-active MOFs, one can provide clear insight into the nature of electrochemical energy storage mechanisms not only for MOFs, but also for all other materials with strongly correlated electronic structures.

저자 스포트라이트: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks  

Ex situ magnetic surveys can directly provide bulk and local information on a magnetic electrode to reveal its charge storage mechanism step by step. Herein, electron spin resonance (ESR) and magnetic susceptibility are demonstrated to monitor the evaluation of paramagnetic species and their concentration in a redox-active metal-organic framework (MOF).

산화 환원 활성 금속-유기 프레임워크의 고체 전기화학에서 중간체의 자기 측정 특성 분석

Electrochemical energy storage has been a widely discussed application of redox-active metal-organic frameworks (MOFs) in the past 5 years. Although MOFs ...