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Title: Extraordinarily large perpendicular magnetic anisotropy in epitaxially strained cobalt-ferrite Co{sub x}Fe{sub 3−x}O{sub 4}(001) (x = 0.75, 1.0) thin films

Perpendicular magnetic anisotropy (PMA) of cobalt-ferrite Co{sub x}Fe{sub 3-x}O{sub 4} (x = 0.75 and 1.0) epitaxial thin films grown on MgO (001) by a reactive magnetron sputtering technique was investigated. The saturation magnetization was found to be 430 emu/cm{sup 3} for x = 0.75, which is comparable to that of bulk CoFe{sub 2}O{sub 4} (425 emu/cm{sup 3}). Torque measurements afforded PMA constants of K{sub u}{sup eff}=9.0 Merg/cm{sup 3} (K{sub u}=10.0 Merg/cm{sup 3}) and K{sub u}{sup eff}=9.7 Merg/cm{sup 3} for x = 0.75 and 1.0, respectively. The value of K{sub u}{sup eff} extrapolated using Miyajima's plot was as high as 14.7 Merg/cm{sup 3} for x = 1.0. The in-plane four-fold magnetic anisotropy was evaluated to be 1.6 Merg/cm{sup 3} for x = 0.75. X-ray diffraction measurement revealed our films to be pseudomorphically strained on MgO (001) with a Poisson ratio of 0.4, leading to a considerable in-plane tensile strain by which the extraordinarily large PMA could be accounted for.
Authors:
; ; ; ; ;  [1] ; ;  [2] ;  [3]
  1. Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan)
  2. Photon Factory and Condensed Matter Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan)
  3. Division of Physics, Graduate School of Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo (Japan)
Publication Date:
OSTI Identifier:
22217909
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 103; Journal Issue: 16; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; COBALT; COBALT OXIDES; DEPOSITION; EPITAXY; FERRITES; LAYERS; MAGNESIUM OXIDES; MAGNETIZATION; MAGNETRONS; POISSON RATIO; SATURATION; SPUTTERING; STRAINS; THIN FILMS; TORQUE; X-RAY DIFFRACTION