Modification of structure and magnetic anisotropy of epitaxial CoFe2O4 films by hydrogen reduction

被引：11

作者：

Chen, Aiping ^{[1
]}

Poudyal, Narayan ^{[2
]}

Xiong, Jie ^{[1
]}

Liu, J. Ping ^{[2
]}

Jia, Quanxi ^{[1
]}

机构：

[1] Los Alamos Natl Lab, Ctr Integrated Nanotechnol CINT, Los Alamos, NM 87545 USA

[2] Univ Texas Arlington, Dept Phys, Arlington, TX 76019 USA

来源：

APPLIED PHYSICS LETTERS | 2015年 / 106卷 / 11期

关键词：

THIN-FILMS;

D O I：

10.1063/1.4915504

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Heteroepitaxial CoFe2O4 (CFO) thin films with different thicknesses were deposited on MgO (001) substrates. The as-deposited CFO films show a clear switching of magnetic anisotropy with increasing film thickness. The thinner films (< 100 nm) show a perpendicular magnetic anisotropy due to the out-of-plane compressive strain. The thicker films exhibit an in-plane easy axis owing to the dominating shape anisotropy effect. The magnetostriction coefficient of CFO films is estimated to be lambda([001]) = -188 x 10(-6). Metallic CoFe2 films were obtained by annealing the as-deposited CFO films in forming gas (Ar 93% + H-2 7%) at 450 degrees C. XRD shows that CoFe2 films are textured out-of-plane and aligned in-plane, owing to lattice matching between CoFe2 and MgO substrate. TEM results indicate that as-deposited films are continuous while the annealed films exhibit a nanopore mushroom structure. The magnetic anisotropy of CoFe2 films is dominated by the shape effect. The results demonstrate that hydrogen reduction can be effectively used to modify microstructures and physical properties of complex metal oxide materials. (C) 2015 AIP Publishing LLC.

引用

页数：4

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