Growth mode and properties of Mn–Co–Ni–O NTC thermistor thin films deposited on MgO (100) substrate by laser MBE

Abstract

Mn 1.56 Co 0.96 Ni 0.48 O 4-δ thin films were deposited on MgO (100) substrate using laser molecular beam epitaxy (LMBE) technique at the temperature range of 300–600°C under oxygen partial pressure of 5 × 10-3 Pa. The effect of growth temperature on microstructure and electrical properties as well as the growth mode were studied using XRD, RHEED, AFM and resistance–temperature measurements. The results showed that all prepared thin films underwent epitaxial growth along the single-(100) orientation direction of the MgO substrate from 3D-island mode to 2D layer-by-layer mode, and exhibited good crystallinity and NTC thermistor behavior. Their resistance at room temperature can be in the range of 10–50 MΩ together with a B-value of about 3300 K, which are desirable for a wide range of practical applications of the NTC thermistors.