journal article·2021-08-01Open access

Reduced magnetocrystalline anisotropy of CoFe2O4 thin films studied by angle-dependent x-ray magnetic circular dichroism

Yosuke Nonaka, Yuki K. Wakabayashi, Goro Shibata, Shoya Sakamoto, Keisuke Ikeda, Zhendong Chi, Yuxuan Wan, Masahiro Suzuki, Tsuneharu Koide, Masaaki Tanaka, Ryosho Nakane, Atsushi Fujimori

AIP Advances· Volume 11· Issue 8

Abstract

Spinel-type CoFe2O4 is a ferrimagnetic insulator with the Néel temperature exceeding 790 K, and it shows strong cubic magnetocrystalline anisotropy (MCA) in bulk materials. However, when a CoFe2O4 film is grown on other materials, its magnetic properties are degraded so that so-called magnetically dead layers are expected to be formed in the interfacial region. We investigate how the magnetic anisotropy of CoFe2O4 is modified at the interface of CoFe2O4/Al2O3 bilayers grown on Si(111) using x-ray magnetic circular dichroism. We find that the thinner CoFe2O4 films have significantly smaller MCA values than bulk materials. The reduction in MCA is explained by the reduced number of Co2+ ions at the Oh site, as reported by a previous study [Wakabayashi et al., Phys. Rev. B 96, 104410 (2017)].
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Research context

OpenAlex topics: Magnetic Properties and Synthesis of Ferrites · Magnetic properties of thin films · Iron oxide chemistry and applications

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

Affiliations

Department of Physics, The University of Tokyo 1 , Bunkyo-ku, Tokyo 113-0033, Japan

Department of Electrical Engineering and Information Systems, The University of Tokyo 2 , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

Department of Applied Physics, Tokyo University of Science 3 , Katsushika-ku, Tokyo 125-8585, Japan

Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) 4 , Tsukuba, Ibaraki 305-0801, Japan

Center for Spintronics Research Network, Graduate School of Engineering, The University of Tokyo 5 , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

Institute for Innovation in International Engineering Education, The University of Tokyo 6 , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

Department of Applied Physics, Waseda University 7 , Shinjuku-ku, Tokyo 169-8555, Japan

Funding

Japan Society for the Promotion of Science · Photon Factory Program Advisory Committee · Materials Education Program for the Futures Leaders in Research, Industry and Technology, University of Tokyo · Advanced Leading Graduate Course for Photon Science, University of Tokyo · JSPS Research Fellowship Program for Young Scientists · Center for Spintronics Research Network, University of Tokyo

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