Perpendicular Magnetic Anisotropic NiCo2O4 Epitaxial Films with Tunable Coercivity

Ferrimagnetic NiCo2O4 (NCO) films with perpendicular magnetic anisotropy, 12.5 nm in thickness, are epitaxially deposited on (001) MgAl2O4 single-crystalline substrates by pulsed laser deposition. It is observed that the coercive field of the NCO films can be tuned systematically by about 20 times, while keeping the large perpendicular magnetic anisotropy, through simply increasing the deposition temperature from 250 to 350 ??C. The increase of resistivity and the increase of low-temperature metal-to-insulator transition temperature suggests increased concentration of defects in NCO films deposited at elevated temperatures. The magnetic and transport characteristics are discussed based on a systematic change in cation valence and coordination in NCO films, as revealed by x-ray photoelectron emission and x-ray absorption spectroscopy measurements. The perpendicular magnetic anisotropy with tunable coercivity makes NCO films promising for multifunctional applications.

Automated summary

In this study, the coercive field of NiCo2O4 films was systematically controlled by varying the deposition temperature while maintaining the perpendicular magnetic anisotropy. The changes in cation valence and coordination in the films were investigated using X-ray photoelectron emission and X-ray absorption spectroscopy, allowing for a better understanding of their magnetic and transport characteristics.