Materials Science Research Lecture

Abstract:

Frustrated magnets can host complex spin textures, leading to unconventional electromagnetic responses. Magnetic frustration may also promote topologically nontrivial spin states such as skyrmions [1], while experimentally skyrmions have largely been observed in noncentrosymmetric materials or interfacial symmetry-broken heterostructures [2]. Recently, we have conceived a new design principle and discovered the emergence of a Bloch-type skyrmion state in a centrosymmetric frustrated triangular-lattice magnet Gd2PdSi3 [3]. We observed a giant topological Hall response, indicating nanometric skyrmions with squeezed emergent magnetic field. We also present recent efforts for synthesis and diffraction studies on single-crystalline new frustrated magnets, showing anomalous transport properties and unconventional modulated and noncollinear magnetic orders enriched by magnetic anisotropy and quadrupole moments [4].

References:

[1] C. D. Batista et al., Rep. Prog. Phys. 79, 084504 (2016).

[2] A. Fert et al., Nat. Natotech. 8, 152 (2013).

[3] T. Kurumaji et al., Science 365, 914 (2019).

[4] T. Kurumaji et al., Phys. Rev. Mater. 6, 094410 (2022),

More about the Speaker:

Dr. Takashi Kurumaji graduated with a B.S. in applied physics from the University of Tokyo (Japan) in 2010. He received his M.S. from the University of Tokyo, where he also received his Ph.D in 2014. From 2014 to 2017, Dr Kurumaji was a postdoctoral researcher at RIKEN Center for Emergent Matter Science in Japan, working with Dr. Yoshinori Tokura. From 2017 to 2020, he was working as a postdoctoral researcher with Dr. Joseph G. Checkelsky at MIT, and from 2020 to 2023 he was a research associate at University of Tokyo working with Dr. Takahisa Arima. Since September 2023, he has become a Research Professor of PMA at Caltech. Dr. Kurumaji's research is centered on the synthesis, discovery, and characterization of novel magnetic materials. He has made key contribution to establishing design principle of magnetic skyrmions and multiferroics. In 2022, he was awarded the Japan Physics Society Young Scientist Award in the field of strongly correlated electron systems.