Faculty Profiles - TANIYAMA Tomoyasu

Strain Mediated in-Plane Uniaxial Magnetic Anisotropy in Amorphous CoFeB Films Based on Structural Phase Transitions of BaTiO3 Single-Crystal Substrates Reviewed

Strain-mediated magnetic response in La0.67Sr0.33MnO3/SrTiO3/La0.67Sr0.33MnO3/BaTiO3 structure Reviewed Open Access

Swain Anupama, Komatsu Katsuyoshi, Itoh Mitsuru, Taniyama Tomoyasu, Gorige Venkataiah

AIP ADVANCES Vol. 8 ( 5 ) 2018.5

Change in magnetization of ferromagnetic Pd(001) ultrathin films induced by the strain effect of BaTiO3 Reviewed

Ban Yusuke, Komatsu Katsuyoshi, Sakuragi Shunsuke, Taniyama Tomoyasu, Kageshima Hiroyuki, Sato Tetsuya

APPLIED PHYSICS LETTERS Vol. 112 ( 14 ) 2018.4

Shinji Isogami, Tomoyasu Taniyama

Physica Status Solidi (A) Applications and Materials Science Vol. 215 ( 6 ) page： 1700762 2018.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley-VCH Verlag

The uniaxial in-plane magnetic anisotropy constants (K1) of amorphous Co10Fe74B16 (CoFeB) films deposited on BaTiO3 (BTO) single-crystal substrates are characterized using a vibrating sample magnetometer. As a result, a significant increase in K1 with temperature is observed by a factor of 26, from 0.267 × 105 erg cm−3 at 300 K to 6.88 × 105 erg cm−3 at 230 K, and the thermal/K1 cycling was reproduced. Estimation of the magnetoelastic effect at the CoFeB/BTO interface demonstrated that the external stress resulting from the structural phase transition from tetragonal to orthorhombic structure in the (001) plane of BTO substrate is the primary cause of the instant magnetic anisotropy in amorphous systems with isotropic magnetostriction such as CoFeB.

DOI： 10.1002/pssa.201700762

High-Rate Performance of LiCoO2 Epitaxial Thin Films with Various Surface Conditions Reviewed

Spin torque in FeRh alloy measured by spin-torque ferromagnetic resonance Reviewed

Tanaka Kensho, Moriyama Takahiro, Usami Takamasa, Taniyama Tomoyasu, Ono Teruo

APPLIED PHYSICS EXPRESS Vol. 11 ( 1 ) 2018.1

Potential of multinary compound Cu2ZnSnS4 single crystals for high-performance environmentally thermoelectric material Reviewed

A. Nagaoka, T. Masuda, S. Yasui, T. Taniyama, Y. Nose

Appl. Phys. Express Vol. 11 ( 5 ) page： 051203 2018

Sou Yasuhara, Shintaro Yasui, Tomoyasu Taniyama, Mitsuru Itoh

MRS Advances Vol. 3 ( 22 ) page： 1243 - 1247 2018

Publishing type：Research paper (scientific journal)

© Materials Research Society 2018. Lithium ion batteries with high-rate performance have been demanded since electric and hybrid vehicles are released. It is known that high interfacial resistance between electrode and electrolyte prevents intercalation of lithium ions. We investigated high-rate capability of typical LiCoO2 cathode with various surface morphologies using epitaxial thin films prepared by pulsed laser deposition. As a result, high-rate performance in (104)LiCoO2 thin films was enhanced by an increase of (110)LiCoO2 facet density because diffusion coefficient of (110)LiCoO2 was larger than that of (104)LiCoO2. Therefore, a control of crystal plane at the surface is a key point for high-rate performance.

DOI： 10.1557/adv.2018.253

Thermally driven magnetization switching of perpendicularly magnetized multilayers Reviewed

Tomoyasu Taniyama, Yasuhiro Shirahata, Ryota Shiina, Eiji Wada, Mitsuru Itoh

2017 IEEE 17th International Conference on Nanotechnology, NANO 2017 page： 1023 - 1026 2017.11

Language：English Publishing type：Research paper (international conference proceedings) Publisher：Institute of Electrical and Electronics Engineers Inc.

Thermally driven magnetization switching of perpendicularly magnetized [Cu/Ni] multilayer/BaTiO3(100) heterostructures is demonstrated. While the magnetization of the multilayer shows the out-of-plane magnetic anisotropy in the tetragonal phase of BaTiO3 at room temperature, the magnetization orientation is found to switch from the out-of-plane to the in-plane in the rhombohedral phase below 180 K. The magnetization switching is attributed to the interfacial compressive strain transfer from BaTiO3 to [Cu/Ni] due to the structural phase transitions of BaTiO3. Magneto-optical polar Kerr measurement in the rhombohedral phase with and without applying an electric field supports the description that the magnetization switching arises from the compressive strain at the interface induced by the structural phase transition from the orthorhombic to rhombohedral phases.

DOI： 10.1109/NANO.2017.8117394