Evaluation of structural and electrical properties of multicomponent spinel oxide thin films deposited via spray pyrolysis technique

Abstract

This work reports the preparation of (Mn,Co,Fe,Ni,Cr)3O4 high-entropy spinel oxide in the form of a ∼ 500 nm thin film utilising a facile spray pyrolysis technique. The structural and electrical properties of the layers were characterised after exposure to temperatures in the range of 400–900 °C. The as-deposited layers were amorphous, and crystallised upon heat treatment at 500 °C. Microstructural analyses proved a homogeneous elemental distribution and the desired Fd-3 m cubic spinel structure. Electrical conductivity measurements indicated a dependence on the processing temperature, with the highest electrical conductivity values (∼3 S cm−1 at 700 °C) obtained for layers heat-treated at 700 °C. The spray pyrolysis technique seems to be well suited to fabricating and exploring spinel-based high-entropy oxides synthesized as thin films, and to studying new compositions containing transition metal cations.