(1. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China)
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DOI:
10.7502/j.issn.1674-3962.2013.06.01
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Abstract:
This article introduces recent advances in study of exchange couplings in magnetic films. The Ferromagnetic(FM)/Antiferrromagnetic(AF)/Ferromagnetic(FM) trilayers are prepared by magnetron sputtering. Component, interface and microstructure of magnetic films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), et al. Magnetic and magnetotransport properties were characterized by superconducting quantum interference device (SQUID). The competition between interlayer and interfacial exchange couplings is found to be temperature dependent in Co / AF / Fe trilayers. The strong effects of ferromagnetic materials on exchange couplings are observed at different temperatures in FM1/Cr2O3/FM2 trilayers with FM ? Co, Fe or Ni80Fe20. The changes of anisotropy of FM and spin-asymmetry of the reflection coefficients for FM contacted antiferromagnetic layer greatly influence the strengths of interfacial and interlayer couplings of the trilayers. Strong effects of ferromagnetic layers on exchange coupling of FM/AF bilayer are observed, which are related to anisotropy of FM more strongly than saturation magnetization. Through magnetic field cooling and applying set magnetic field, four states of exchange bias have been achieved in [Pt/Co]/NiFe/NiO heterostructures with orthogonal easy axes, and also the isothermal tunable exchange bias has been obtained. The exchange bias in the Co/NiO antidot arrays and continuous films has been investigated. Compared with the continuous films, an enhanced or decreased exchange bias field and a higher thermal stability have been found in the antidot arrays.