[17a-501-1~12] 10.1 Emerging materials in spintronics and magnetics (including fabrication and charactrization methodologies)

▼ [17a-501-5] Electronic structure and magnetic properties of magnetic dead layers in epitaxial CoFe₂O₄/Al₂O₃/Si(111) films studied by X-ray magnetic circular dichroism (XMCD)

〇Yuuki Wakabayashi¹, Yosuke Nonaka², Yukiharu Takeda³, Shoya Sakamoto², Keisuke Ikeda², Zhendong Chi², Goro Shibata², Yuji Saitoh³, Hiroshi Yamagami^3,4, Masaaki Tanaka¹, Atsushi Fujimori², Ryosho Nakane¹ (1.Eng. Univ. of Tokyo, 2.Phys. Univ. of Tokyo, 3.JAEA, 4.Kyoto Sangyo Univ.)

Keywords:XMCD, oxide films, spintronics

The spin filter effect through a CoFe₂O₄ tunnel barrier has a potential ability for generating a highly spin-polarized electron current. Nevertheless, the experimental spin-polarization value estimated from tunnel magnetoresistance has been much less than expectation [1, 2], and many researchers have begun to point out the degradation of the electronic structure and magnetism due to spontaneously-formed structural disorder. It is plausible from the general recognition that magnetic dead layers formed at heterointerfaces cause to degrade ferrimagnetic ordering further with decreasing thickness, however, the magnetism of CoFe₂O₄ layers with various thicknesses have not yet systematically investigated. In this study, we present the electronic structure and magnetic properties of CoFe₂O₄(111) layers with various thicknesses using XAS and XMCD.