Effect of oxygen vacancy modification on electrical properties of La(Cr₀.₂Mn₀.₂Fe₀.₂Co₀.₂Ni₀.₂)O₃ high-entropy perovskite oxide films

Abstract

The epitaxial La(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 (L5BO3) thin films with varying oxygen vacancies were prepared on (001) SrTiO3 substrates in this work. These thin films exhibit a high degree of crystallinity and prominent semiconductor characteristics. The valence state of the B-site elements is influenced by the introduction of oxygen vacancies, which in turn affects the spin state. Electrical properties were investigated across a broad temperature range (150–400 K), demonstrating significant resistivity variations of up to 3 orders of magnitude as a function of oxygen vacancies. The corresponding mechanisms of small polaron hopping and variable range hopping are discussed. This work explores the effect of oxygen vacancies on the structure and performance of L5BO3 high-entropy oxide films prepared under various oxygen pressures, offering foundational insights into the compositional manipulation of high-entropy oxides.