IMX Talks - Tailored magnetic garnet films with engineered magnetization for spin-wave and magneto-optical applications

We present a series of studies on magnetic garnet films with tailored microstructures and engineered magnetization, targeting spin-wave and magneto-optical device applications. First, two-dimensional magnonic crystals are demonstrated using yttrium iron garnet (YIG) films with copper (Cu) patterning, which effectively suppresses the spatial distribution of shape magnetic anisotropy inherent to patterned structures, enabling spin-wave waveguides with well-defined propagation characteristics. Second, multilayer epitaxial single-crystal magnetic garnet films fabricated by ion beam sputtering yield perpendicular magnetic anisotropy domain structures with characteristic lengths from the nanometer to micrometer scale, which are exploited as magneto-optical lenses for beam-shaping and holographic applications. Third, toward on-chip photonic integration, optical isolators compatible with integrated optical circuits are developed alongside a laser annealing process that enables local crystallization of garnet films on non-garnet substrates, circumventing thermal budget constraints and opening a route to silicon-compatible magneto-optical isolation. These results collectively illustrate how deliberate processing and magnetization engineering of garnet films can address key challenges in both magnonics and integrated photonics.

Bio: Taichi Goto received the M.S. degree in Electrical and Electronic Engineering and the Ph.D. degree from the Graduate School of Engineering, Toyohashi University of Technology, Japan, in 2009 and 2011, respectively.
He was a JSPS Research Fellow (DC1 and PD), including an overseas fellowship. From 2011 to 2013, he was a Postdoctoral Associate with the Massachusetts Institute of Technology (MIT), Cambridge, MA, USA. From 2013 to 2022, he was an Assistant Professor with Toyohashi University of Technology. He was also a JST PRESTO Researcher from 2015 to 2019, and a Visiting Researcher with MIT from 2016 to 2020.
Since 2022, he has been an Associate Professor with the Research Institute of Electrical Communication, Tohoku University, Sendai, Japan. He also holds the titles of Tohoku University Distinguished Researcher and TI-FRIS Fellow at the Frontier Research Institute for Interdisciplinary Sciences.
He has authored more than 70 peer-reviewed journal articles, filed 21 patents, and delivered numerous invited talks at international conferences. His work on functional microdevices based on magnetic interference was recognized with the Young Scientists' Prize from the Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology (MEXT), Japan, in 2019. His research interests include spin-wave devices, magneto-optical devices, and the development of related magnetic and photonic materials.
He is a member of the Institute of Electrical and Electronics Engineers (IEEE), the Materials Research Society (MRS), the Magnetics Society of Japan, the Institute of Electrical Engineers of Japan (IEEJ), and the Japan Laser Society.