Ferrimagnetic and Metallic Properties of (001) NiCo2O4 Films Fabricated at Various Oxygen Pressures

초록

Epitaxial (001) NiCo2O4 films with perpendicular magnetic anisotropy were grown on (001) MgAl2O4 at various oxygen pressures of 10-200 mTorr using pulsed laser deposition. X-ray diffraction suggested that the lattice constant, crystallinity, and deposition rate displayed distinctive changes around 50 mTorr. The temperaturedependent resistance displayed an insulating behavior in the films grown below 15 mTorr but a metallic one in the films grown above 20 mTorr. Magneto-optical Kerr effect measurement suggested that the NiCo2O4 films grown above 15 mTorr are ferrimagnetic at room temperature and possess a distinctive perpendicular magnetic anisotropy. The ferrimagnetic-to-paramagnetic transition temperature reached a maximum of similar to 385 K at 50 mTorr. During the magnetic reversal, the density of small nucleated domains increased with increasing oxygen pressure from 20 to 200 mTorr, and exhibited metallic ferrimagnetism at room temperature. Consequently, the optimal growth condition for magnetic device applications of NiCo2O4 films is believed to be 50-200 mTorr at 320 degrees C.

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