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

Abstract

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. V C 2014 AIP Publishing LLC. [http://dx

Electrical and Magnetic Properties Modification in Heavy Ion Irradiated Nanograin NixCo(3–x)O4 Films

“…Though the cause of this large coercivity increase is not clear, some speculations can be made to direct future work. Having multiple phases, including ferrimagnetic spinel(s) and antiferromagnetic NiO, could cause interfacial effects leading to exchange bias and increased coercivity. − It has been seen that exchange bias can be caused by interface phases at grain boundaries or different collinear–​noncollinear spin interfaces as well. − No exchange bias was observed in our experiments even though the low-temperature hysteresis curves were taken after field cooling in 500 Oe.…”

Microstructure, magnetic properties and the giant magnetoimpedance effect of amorphous CoSiB thin films deposited by different preparation methods

“…The IBAD method is combined with physical vapor deposition (PVD) and independent ion beam bombardment. Thus, this method is typically used to independently control film's composition and structure and so on [13]. Especially, during the IBAD deposition process, the slow rate of deposition makes the atoms have enough time to rearrange on the surface, and the CoSiB system can explore more stable configurations before buried by the upcoming atoms.…”