BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Memento EPFL// BEGIN:VEVENT SUMMARY:IMX Talks - Functional topological antiferromagnet DTSTART:20211013T150000 DTEND:20211013T160000 DTSTAMP:20260408T121153Z UID:a52cae4716ecb75a41798e33f8a09f7a6e849960f299faa87c356cf7 CATEGORIES:Conferences - Seminars DESCRIPTION:Prof. YoshiChika Otani\, ISSP University of Tokyo Kashiwa 277- 8581 Japan\, CEMS RIKEN Wako 351-0198 Japan\, CREST JST Kawaguchi 332-0012 Japan\, Trans-scale Quantum Science Institute University of Tokyo Bunkyo- ku 113-0033 Japan\nChiral antiferromagnets Mn3X (X=Sn and Ge) exhibit sign ificant magnetoelectric\, thermoelectric\, and optical responses such as a nomalous Hall effect (AHE)\, anomalous Nernst effect (ANE)\, and magneto-o ptical Kerr effect (MOKE)\; their magnitudes reach almost the same as thos e of ferromagnetic metals. These characteristic properties of Mn3X imply t hat the spin Hall effect (SHE) could also occur. Our recent study demonstr ated that a novel type of contribution to the SHE (magnetic SHE\, MSHE) an d the inverse SHE (MISHE) absent in nonmagnetic materials could be dominan t in the antiferromagnets\, Mn3X. We attribute this dominant magnetic mech anism to the momentum-dependent spin splitting produced by the noncollinea r magnetic order\,i.e.\, the cluster magnetic octupole (CMOP)\, comprising two sets of three spin sublattices. Moreover\, the cluster magnetic octup ole takes ferroic order on the Kagome lattice\, macroscopically breaking t he time-reversal symmetry. Previous studies also revealed that the cluster magnetic octupole\, not the magnetic dipole\, plays an essential role as the magnetic order parameter for antiferromagnetic domains and domain wall s.\nIn the first half of this talk\, we will introduce our recent experime ntal results on the magnetic spin Hall effects (MSHE)\, particularly angul ar dependent spin densities appearing on the surface of a focused ion beam fabricated Mn3Sn epitaxial thin slab. We will discuss the new functionali ty for magnetic manipulation we could obtain from the MSHE. In the second half\, we will discuss the electrical nucleation\, displacement\, and dete ction of antiferromagnetic domain walls (AFDWs) consisting of the CMOPs. W e will also show some of our recent MOKE measurements for Mn3Ge to discuss the magnetic domain structures. Our findings could provide a guiding prin ciple for engineering the AFDW structure in chiral antiferromagnetic mater ials.\nBio: Prof. YoshiChika Otani received the B.S.\, M.S.\, and Ph.D. de grees from Keio University\, Japan\, in 1984\, 1986\, and 1989. He was a r esearch fellow at the Physics Department of Trinity College Dublin\, the U niversity of Dublin\, Ireland (1989-1991)\, and a researcher at the Labora toire Louis Neel\, CNRS\, France (1991-1992). He was an assistant professo r at the Department of Physics\, Keio University (1992-1995) and an associ ate professor at the Department of Materials Science\, Tohoku University ( 1995-2002). From 2001 to 2012\, Prof. Otani led\, as a team leader\, the Q uantum Nano-Scale Magnetics Research Team at the RIKEN Frontier Research S ystem (FRS). In 2004 he became a professor at the Institute for Solid Stat e Physics (ISSP)\, the University of Tokyo. Since 2013\, Prof. Otani has a lso been the Quantum Nano-Scale Magnetism Research Team leader at the RIKE N Center for Emergent Matter Science (CEMS). He has been working on experi mental spintronics\, studying spin current-related physics in nanoscale de vices consisting of magnetic and non-magnetic materials\, including topolo gical insulators\, chiral antiferromagnets\, and chiral molecules.\n\n  LOCATION:https://epfl.zoom.us/j/67586648183 STATUS:CONFIRMED END:VEVENT END:VCALENDAR