Thickness dependent structural, magnetic, and electronic properties of the epitaxial films of transparent conducting oxide NiCo_2O_4

摘要

We present the thickness dependent structural, magnetic, and transport.properties of transparent conducting spinel NiCo_2O_4 thin films on MgAl_2O_4 (001) substrates. The structural examination of the films reveals that the epitaxial stain is independent of the films' thickness. Electric and magnetic measurements show that the films are metallic with p-type conduction and ferrimagnetic down to 2 unit cells with an enhanced coercive field in the films thinner than 30 unit cells. The low-temperature resistivity data indicate that the observed resistivity minimum results from the disorder-induced quantum interference effects. Our results demonstrate that NiCo_2O_4 may provide an alternative magnetic, conducting medium for spintronics devices.