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Title: Highly spin-polarized current in Co-substituted Fe{sub 3}O{sub 4} epitaxial thin films at room temperature

Epitaxial thin films of cobalt ferrite Co{sub x}Fe{sub 3−x}O{sub 4} (x = 0.0, 0.5, and 1.0) were fabricated on α-Al{sub 2}O{sub 3} (001) substrates using pulsed laser deposition. It was found that the coercive force of the cobalt ferrite films could be tuned by changing the Co content. The films prepared under low oxygen pressure (1.0 × 10{sup −6 }Pa) showed semiconducting behavior even for x = 1.0. X-ray photoelectron spectroscopy revealed that the Co ions were 2{sup +} for all compositions. On the other hand, it was found that the Fe ions were in the Fe{sup 2+}/Fe{sup 3+} valence state, which may cause small-polaron hopping among the Fe-3d electrons in the films. An anomalous Hall effect was observed in the Co{sub 0.5}Fe{sub 2.5}O{sub 4} film even at 300 K, suggesting that carriers in the films were highly spin-polarized at room temperature.
Authors:
; ; ; ;  [1]
  1. Department of Electrical Engineering and Information Systems, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)
Publication Date:
OSTI Identifier:
22402725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 21; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM OXIDES; COBALT; COBALT IONS; COERCIVE FORCE; ENERGY BEAM DEPOSITION; EPITAXY; FERRITES; HALL EFFECT; IRON IONS; IRON OXIDES; LASER RADIATION; PULSED IRRADIATION; SPIN ORIENTATION; SUBSTRATES; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; VALENCE; X-RAY PHOTOELECTRON SPECTROSCOPY