"IEEE Magnetics Society Distinguished Lecturer" Talk_Yayoi Takamura
Tailoring Magnetic Spin Textures in La 0.7 Sr 0.3 MnO 3 -Based Micromagnets
The development of next-generation computing devices based on spintronics and magnonics requires an
understanding of how magnetic spin textures can be tailored in patterned magnetic materials. Within the
wide range of magnetic materials available, complex oxides such as ferromagnetic (FM)
La 0.7 Sr 0.3 MnO 3 (LSMO) provide an ideal platform for tailoring magnetic spin textures when
lithographically patterned as nano/micromagnets. This unique tunability arises due to the strong
interactions among charge, spin, lattice, and orbital degrees of freedom. In this talk I demonstrate how an
intricate interplay exists between shape, magnetocrystalline anisotropy, domain wall, and magnetoelastic
energies due to the unique combination of magnetic parameters associated with LSMO. Using x-ray
photoemission electron microscopy, I will show that the resulting FM spin textures can be controlled
using parameters such as micromagnet shape (circles, squares, triangles, and hexagons with their edges
oriented along different low-index crystallographic directions, with and without their core regions
removed (aka “donut structures”)) and temperature [1]. LSMO nanomagnets are also patterned into
artificial spin-ice (ASI) structures [2]-[4], where large arrays of nanomagnets are arranged in geometries
where all the magnetic interactions cannot be satisfied simultaneously. While one might expect shape
anisotropy to dictate Ising states in the nanomagnets, we observed the formation of both Ising and
complex spin textures (CSTs) which consist of single- and double-vortex structures depending on the
nano-island width and center-to-center spacing. These CSTs alter the nature of dipolar coupling among
nanomagnets, giving rise to exotic physics in the ASI lattices. These studies demonstrate that complex
oxides provide a unique platform for engineering FM spin textures for next-generation spin-based
devices.
[1] M. S. Lee et al., “Tailoring Spin Textures in Complex Oxide Micromagnets,” ACS Nano, 10, 8545
(2016).
[2] R. V. Chopdekar et al., “Nanostructured Complex Oxides as a Route Towards Thermal Behavior in
Artificial Spin Ice Systems,” Phys. Rev. Mater., 1, 024401 (2017).
[3] D. Sasaki et al., “Formation of Complex Spin Textures in Thermally Demagnetized La 0.7 Sr 0.3 MnO 3
Artificial-Spin-Ice Structures,” Phys. Rev. Appl., 17, 064057 (2022).
[4] D. Sasaki et al., “Energetics of Ising-vortex interactions in La 0.7 Sr 0.3 MnO 3 brickwork artificial spin
ices”, Phys. Rev. B., 113, 064416 (2026)
Date and Time
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- Carnegie Mellon University
- Pittsburgh, Pennsylvania
- United States
- Building: Wean Hall
- Room Number: 7500
Speakers
Yayoi Takamura of University of California, Davis
Tailoring Magnetic Spin Textures in La 0.7 Sr 0.3 MnO 3 -Based Micromagnets
Biography:
Yayoi Takamura received the B.S. degree from Cornell University in 1998 and the M.S. and Ph.D. degrees from Stanford University in 2000 and 2004, all in the field of Materials Science and Engineering. She was a postdoctoral researcher at University of California, Berkeley, with Prof. Yuri Suzuki in the Department of Materials Science and Engineering before joining the Department of Materials Science and Engineering at University of California, Davis, in July 2006. She served as the Department Chair from 2020-2025. Her research focuses on the growth of complex oxide thin films, heterostructures, and nanostructures and the characterization of the novel functional properties associated with their interfaces.
Prof. Takamura is a recipient of an NSF CAREER Award, a DARPA Young Faculty Award, and a 2020 University of California, Davis, College of Engineering Mid-Career Research Award.
Prof. Takamura is a Senior Member of the IEEE. She was the General Chair of the 2022 Magnetism and Magnetic Materials (MMM) Conference in Minneapolis, Minnesota, Program Co-Chair of the 2017 MMM Conference in Pittsburgh, Pennsylvania, and Member-at-Large of the American Physical Society’s Topical Group on Magnetism and Its Applications (GMAG). She served as Membership Chair of the IEEE Magnetics Society and is Associate Chair for Conference Finances of its Conference Executive Committee. She is an editor for the Journal of Alloys and Compounds and is a member of the Editorial Advisory Board for the Journal of Applied Physics.