High-Temperature Ferromagnetism of Zn1-xMnxOy Thin Films Synthesized by Pulsed Laser Deposition

Abstract

The paper discusses the findings of the study of the structural and magnetic properties of Zn1-xMnxOy thin films (x = 0-0.08), synthesized by pulsed laser deposition under different conditions. It has been discovered that during the doping, thin films remain single-phased and retain wurtzite structure (ZnO wurz), oriented along the direction (001). It has been determined that thin films obtained under the same synthesis conditions have similar crystallite sizes, which is confirmed by the substitution of Mn2+ ions with Zn2+ ions in the Zn O semiconductor matrix. It has been found that annealing of samples in the oxygen atmosphere increases the surface roughness from 1-3 nm to ~ 10 nm; the higher the concentration of manganese in Zn1-xMnxOy films is, the greater the value of Ra. It has been demonstrated that, at room temperature, all Zn1-xMnxOy thin films (x = 0-0.08) exhibit ferromagnetic behavior, which is more pronounced upon the increase in concentration of oxygen vacancies and manganese in the samples. It is assumed that two mechanisms explaining high-temperature ferromagnetism coexist in the films: the first one is determined by ferromagnetic exchange between Mn2+ cations by means of oxygen vacancies, the second one deals with super-exchange interaction between oxygen vacancies.