Ferrimagnetic and Metallic Behaviors in Epitaxial NiCo2O4 Films Grown on (001)MgAl2O4 at Low Temperatures; 저온에서 (001)MgAl2O4 기판에 증착한 에피탁시 NiCo2O4 박막의 준강자성 및 금속성

초록

Using pulsed laser deposition, we deposited (001) NiCo2O4 films on (001) MgAl2O4 substrates while fixing other deposition parameters and reducing the deposition temperature from 320 ◦C to 100 ◦C. As the deposition temperature decreased to 150 ◦C, X-ray diffraction patterns indicated a decrease in the out-of-plane lattice constant from 8.186 Å to 8.142 Å. Conversely, at a deposition temperature of 100 ◦C, no film peak was observed, supporting the amorphous film. The polar magneto-optical Kerr effect revealed that the coercivity was approximately 1200 Oe in the film grown at 320 ◦C and showed a significant decrease to around 200–300 Oe at the deposition temperatures below 250 ◦C, with no observable perpendicular magnetic anisotropy at the deposition temperature of 100 ◦C. The temperature at which the metal-insulator transition occurred was around 500 K in the film grown at 250 ◦C, and exhibited weakened metallic behavior as the deposition temperature decreased to 150 ◦C. This work demonstrated that even at a low deposition temperature of 150 ◦C, the epitaxial NiCo2O4 film exhibited tetragonal lattice strain, perpendicular magnetic anisotropy, and metallic properties. © 2024 Korean Physical Society. All rights reserved.

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