Exchange bias in polycrystalline magnetite films made by ion-beam assisted deposition
- Author(s): Kaur, M
- Jiang, W
- Qiang, Y
- Burks, EC
- Liu, K
- Namavar, F
- McCloy, JS
- et al.
Published Web Locationhttps://doi.org/10.1063/1.4900747
© 2014 AIP Publishing LLC. 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.
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