Exchange bias in polycrystalline magnetite films made by ion-beam assisted deposition

Journal Article · Fri Nov 07 04:00:00 EST 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4900747· OSTI ID:22308208

Kaur, Maninder; Qiang, You ^[1]; Jiang, Weilin ^[2]; Burks, Edward C.; Liu, Kai ^[3]; Namavar, Fereydoon ^[4]; McCloy, John S. ^[2]

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1. Department of Physics, University of Idaho, Moscow, Idaho 83844 (United States)
2. Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)
3. Department of Physics, University of California, Davis, California 95616 (United States)
4. University of Nebraska Medical Center, Omaha, Nebraska 68198 (United States)

Iron oxide films were produced using ion-beam-assisted deposition, and Raman spectroscopy and x-ray diffraction indicate single-phase magnetite. However, incorporation of significant fractions of argon in the films from ion bombardment is evident from chemical analysis, and Fe/O ratios are lower than expected from pure magnetite, suggesting greater than normal disorder. Low temperature magnetometry and first-order reversal curve measurements show strong exchange bias, which likely arises from defects at grain boundaries, possibly amorphous, creating frustrated spins. Since these samples contain grains ∼6 nm, a large fraction of the material consists of grain boundaries, where spins are highly disordered and reverse independently with external field.

• OSTI ID: 22308208
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 17 Vol. 116; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHEMICAL ANALYSIS
CRYSTAL DEFECTS
DEPOSITION
FILMS
GRAIN BOUNDARIES
ION BEAMS
IRON OXIDES
MAGNETITE
POLYCRYSTALS
RAMAN SPECTROSCOPY
SPIN
X-RAY DIFFRACTION