The family of complex oxides display intriguing functional properties with applications in emerging fields such as neuromorphic computing and spintronic devices due to their strong interactions between the charge, spin, lattice, and orbital degrees of freedom. Interfacial interactions that occur in complex oxide heterostructures and upon micro-/nanoscale patterning provide additional means to tailor their functional properties. In this talk, I will discuss two recent scientific adventures my group has explored with complex oxide heterostructures and patterned microstructures. In the first adventure, magnetic exchange interactions at the interface between two ferromagnetic oxides, La_0.67Sr_0.33CoO₃ (LSCO) and La_0.67Sr_0.33MnO₃ (LSMO) were investigated.[1] The LSCO/LSMO interface was characterized by a soft LSCO layer with magnetically active Co²⁺ ions which formed due to the combined effect of the formation of oxygen vacancies and interfacial charge transfer. As a result, a magnetic soft/hard interface formed in the interior of the LSCO layer which led to an exchange bias effect. The nature of these interfacial phenomena could be carefully controlled with parameters such as the LSCO layer thickness, epitaxial strain, and the layer stacking order. In the second adventure, an ion implantation-based patterning process was used to define magnetic islands embedded within a non-magnetic matrix in an LSMO thin film.[2] X-ray photoemission electron microscopy was used to image the resulting ferromagnetic spin textures, and these images demonstrate that an intricate interplay exists various magnetic energy terms, including shape and magnetocrystalline anisotropy energies, domain wall energies, and magnetoelastic effects. These adventures demonstrate the potential for complex oxide heterostructures for next generation information technology device.

[1] B. Li, Y. Takamura, et al., APL., 105, 202401 (2014); A.M. Kane, Y. Takamura, et al., ACS Appl. Mater. & Inter., 12, 45437 (2020); M. Feng, Y. Takamura, et al., JAP, 132, 195301 (2022); M. Feng, Y. Takamura et al., ACS Appl. Mater. & Inter., 15, 53086, (2023)

[2] Y. Takamura et al., Nano Letters, 6 1287 (2006); Y. Takamura et al., PRL, 111, 107201 (2013), M.S. Lee, Y. Takamura et al., ACS Nano, 10, 8545 (2016); Y. Takamura et al., in preparation

Biography:

Yayoi Takamura received her B.S. from Cornell University in 1998 and her M.S. and Ph.D. degrees from Stanford University in 2000 and 2004, respectively, all in the field of Materials Science and Engineering. She was a postdoctoral researcher at UC Berkeley with Prof. Yuri Suzuki in the Dept. of Materials Science and Engineering before joining the Dept. of Materials Science and Engineering at UC Davis in July 2006. From 2020-2025, she served as Department Chair. 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 the NSF CAREER Award, the DARPA Young Faculty Award, and the 2020 College of Engineering Mid-Career Research Award. She is serving as an IEEE Magnetics Society Distinguished Lecturer for 2025-2027.

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