Film structure and magnetic properties of ferromagnetic amorphous Bi2O3-Fe2O3-PbTiO3 films prepared by rf-reactive sputtering

Abstract
Amorphous‐like oxide films of the Bi2O3‐Fe2O3‐PbTiO3 ternary system prepared by rf‐reactive sputtering exhibit ferromagnetism and ferroelectricity simultaneously well above room temperature. In this paper, we have investigated the relation between the film structure and the magnetic properties of the films by means of x‐ray diffractometry, transmission electron microscopy, magnetization measurement with a vibrating‐sample magnetometer, and Mössbauer spectroscopy. The film composition used in the study is 0.16Bi2O3‐0.74Fe2O3‐0.10PbTiO3, which attains the maximum magnetization in this ternary system. It is revealed that ferromagnetism originates from the amorphous part in the films.