Magnetic domain structure of the ferrimagnetic (001) NiCo2O4 film with perpendicular magnetic anisotropy

초록

A 65-nm thick epitaxial (001) NiCo2O4 film that has metallic and ferrimagnetic properties at room temperature was grown on a (001) MgAl2O4 substrate. Evolutions in magnetic domains of the ferrimagnetic (001) NiCo2O4 film with perpendicular magnetic anisotropy were observed using polar magneto-optical Kerr effect microscopy with changes in magnetic field, temperature, or time. The magnetic domain structure in the magnetic field exhibited noticeable changes around a coercive field; whereas, its change in temperature or time at a fixed magnetic field was indistinct. This suggests that the ferrimagnetic (001) NiCo2O4 film has a relatively stable magnetic domain structure in comparison with Co alloy films with perpendicular magnetic anisotropy and fast domain wall motion. Conclusively, the magnetic domain variation in the NiCo2O4 film signified that the magnetization process at an early stage was mainly caused by domain rotation behavior rather than domain wall motion.

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