NANOSCALE PHYSICAL PROPERTIES
YOSHICHIKA OTANI LAB.
INTRODUCTION OF LABORATORY
Otani group has been carrying out spintronics research since 2004. The group has developed static and dynamic electrical generation and detection techniques of the spin angular momentum flow, called spin current, the fundamental physical entity responsible for various spintronics phenomena such as a nonlocal spin valve, spin-transfer torque, spin-orbit torque, Edelstein effects, and spin Hall effects. The group’s research interests have evolved into the development and elucidation of various novel spin-mediated conversion phenomena among quasiparticles such as electrons, magnons, phonons, and photons. These interconversion phenomena mentioned above arise from spin-orbit interaction inside, on surfaces, and at interfaces of solids. The group has demonstrated a significant Rashba Edelstein effect at the interface of various metal-oxide interfaces. The group has also recently discovered a new class of spin Hall effects, i.e., magnetic spin Hall effects in quantum materials, Mn3X (X=Sn and Ge) in collaboration with colleagues in the quantum materials group. The magnon-phonon coupling is also an important research topic in the group. The group has established the acoustic spin pumping method to inject an acoustic wave into ferromagnetic thin films. This method enabled the group to study the Magneto-rotation coupling, which is fundamentally different from the magneto-elastic coupling. Thereby, the group has succeeded in observing the 100 % rectification of surface acoustic waves propagating in an ultra-thin ferromagnetic thin film. The group has also demonstrated the manipulation of Skyrmion creation and annihilation by using surface acoustic waves. The final goal of the group is the realization and understanding of new spin-mediated coupling among various quasiparticles.
ノンコリニア反強磁性体の磁気スピンホール効果: 従来のスピンホール効果に対する磁化の寄与の発見. (a)微細加工されたMn3Snの上に強磁性体と非磁性体の電極が蒸着されたスピン蓄積検出素子の概略図. (b) 磁気逆スピンホール効果に由来するスピン蓄積信号. Mn3Snのスピン状態を逆向きにすると, ヒステリシスの符号が逆になる.
分子/金属界面のスピン流-電流変換効果：スピンポンピング法による. (a)分子/金属(PbPc/Cu)界面とスピンポンピングの概略図. (b)スピンポンピングにより誘起されたスピン流-電流変換由来の電圧信号. (c)Cu(111)表面上に吸着された単層PbPc膜の走査型トンネル顕微鏡像.
MESSAGE
CHALLENGING RESEARCH TO MANIPULATE SPINS TO GO BEYOND THE LIMITS FOR NEXT GENERATION SCIENCE.
In near future, current electronics for information technologies are expected to encounter fundamental limits in terms of physical size and energy efficiency as a consequence of advanced miniaturization. Spintronics, utilizing the spin of electrons to convey information, is anticipated to offer further development as well as the solution to the above problem. We put our focus on the novel properties of such spins emerging particularly from the interaction among spins and nano-scale magnets.
キーワード
Spin current / spin Hall effect / spintronics / spin conversion / Edelstein effect / magnetoresistance / spin-orbit interaction / spin accumulation / spin injection / spin torque / metal spintronics / magnetic domain structure / strong coupling / international center formation / spin conversion research / Young people development / Base formation / Magnetoresistance / Ferromagnetic wires / Ferromagnetic dots array / Domain structure /Ferromagnetic wire / ferromagnetic particle lattice / spin-activated interaction / magnonics / spintronics / magnon-phonon coupling / magnon-phonon coupling / spin-photonics / Mr. Non-Reciprocity / Magnetic rotational coupling / Spin-rotational coupling / Spin-charge conversion / Magnon-phonon coupling / Spin-rotational coupling / Spin-charge conversion Phonon coupling / Magnetoelastic coupling / International symposium / Spin conversion function / Spin-orbit torque / International joint research / Information dissemination / Synergy effect / Spin angular momentum / Spin conversion research center formation / Thermal-mechanical spin conversion / Optical spin conversion / Electromagnetic spin conversion / Spin Seebeck effect / International competitiveness / International conferences / Internships / International activities / Formation of international centers for spin conversion / International collaboration / Joint research / Human resource development / Antiferromagnet / Antiferromagnetic domain wall / Exchange coupling / Antiferromagnets / antiferromagnetic domain wall /Exchange coupling / domain wall nucleation / Magneto-optical effect / Domain wall nucleation / Magneto-optical effect / Spin charge conversion / Electric field-induced magnetization reversal / Spin momentum locking / Magnetic spin conversion / Spin-current current mutual conversion / Spin-current conversion / Metal-insulator transition / Magnetic phase transition / Spin-torque magnetic resonance / Nonlocal spin injection / Spin relaxation / Spin absorption / Domain wall motor / Ratchet drive / Molecular motor / Asymmetric potential / Nanodomain wall / Metal nanomagnetism / Local magnetic field / Dipole interaction Action / ferromagnetic two-dimensional lattice / magnetic anisotropy / magnetization reversal / microfabrication / magnetic flux penetration / superconducting thin film / magnetic flux quantum / ferromagnetic fine particles / composite structure film
PROFILE : Professor Yoshichika Otani
Prof. YoshiChika Otani received the B.S., M.S., and Ph.D. degrees from Keio University, Japan, in 1984, 1986, and 1989. He was a research fellow at the Physics Department of Trinity College Dublin, the University of Dublin, Ireland (1989?1991), and a researcher at the Laboratoire Louis Neel, CNRS, France (1991?1992). He was an assistant professor at the Department of Physics, Keio University (1992?1995) and an associate professor at the Department of Materials Science, Tohoku University (1995?2002). From 2001 to 2012, Prof. Otani led, as a team leader, the Quantum Nano-Scale Magnetics Research Team at the RIKEN Frontier Research System (FRS). In 2004 he became a professor at the Institute for Solid State Physics (ISSP), the University of Tokyo. Since 2013, Prof. Otani has also been the Quantum Nano-Scale Magnetism Research Team leader at the RIKEN Center for Emergent Matter Science (CEMS). He has been working on experimental spintronics, studying spin current-related physics in nanoscale devices consisting of magnetic and non-magnetic materials, including topological insulators, chiral antiferromagnets, and chiral molecules.
STUDENT VOICE : AYUKO KOBAYASHI
Prof. Otani possesses an in-depth understanding of physics, thus he naturally serves as a role model for students. He not only inspires students and values their opinions on their desired paths, but also leads them with clear guidance that prioritizes outstanding results. Students are expected to proactively give presentations at international conferences and join collaborative research with overseas institutions, which is supported by our day-to-day discussions with many non-Japanese researchers. With these experiences, many students have chosen to follow carrier paths outside of Japan after graduation. The laboratory members share a strong common purpose in solving challenging problems in modern society, dedicating ourselves as a team.
SOLID STATE PHYSICS AND CHEMISTRY
We are conducting complementary research on magnetic physical phenomena that are characteristic of nanoscale magnetic materials.
Yoshichika Otani Lab.,
Department Of Advanced Materials Science,
Graduate School of Frontier Sciences,
The University of Tokyo
Kashiwanoha 5-1-5,
Kashiwa,Chiba 277-8561, Japan
+81-4-7136-3488
+81-4-8467-9681
yotani@issp.u-tokyo.ac.jp
The Goal of Applied Physics
The goal of Applied Physics is to develop a stage = “new material” that can manipulate undeveloped degrees of freedom, to explore unknown phenomena created from that stage and to bring out excellent functions, and to bring out its excellent functions. The purpose is to contribute to the development of human society by elucidating the mechanisms and developing application fields for these phenomena and functions.
AMS (Advanced Materials Science)
Department Office
AMS (Advanced Materials Science),
Graduate School of Frontier Sciences,
The University of Tokyo
Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8561, Japan
Email : ams-office(at)ams.k.u-tokyo.ac.jp
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