Low-temperature (<300 °C) growth and characterization of single-[100]-oriented Mn-Co-Ni-O thin films

Single-[100]-oriented Mn1.56Co0.96Ni0.48O4 (MCN) thin films were grown on amorphous surfaces of thermally oxidized Si(100) substrates at low temperatures below 300 °C using laser molecular beam epitaxy (LMBE) technique. The structural and electrical properties of the films were investigated. The film grown at the optimum temperature of 250 °C was atomically smooth with a root-mean-square roughness of 0.373 nm over 2×2 μm2 on the surface. The current-voltage characteristics showed the Ohmic behavior, and the resistance-temperature relationship exhibited negative temperature coefficient (NTC) thermistor characteristics. The electron transport of the single-[100]-oriented MCN thin film was found to be by nearest-neighbor hopping. The successful growth of single-oriented MCN thin films opens a door for studying the influence of crystallographic orientation on the electron conduction mechanisms and on the properties of MCN thin films. This study also suggests that LMBE is preferable for fabricating high-quality MCN thin films for NTC thermistors and bolometer infrared detectors.