Effects of high-temperature annealing on amorphous BiFeO3 with nonmagnetic substitutions

• Published in: Applied physics letters 1991-05, Vol.58 (21), p.2441-2443
• Main Authors: UMA MAHESHWAR RAO, B, SRINIVASAN, G
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic properties and materials; Magnetic properties of surface, thin films and multilayers; Physics
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.104867

We report on the preparation of amorphous (a-) insulators with the highest saturation induction ever achieved. Samples of a-(1 − x)BiFeO3−xABO3 (AB=PbZr, PbTi, BaTi) with x=0–0.6 were prepared by rf sputtering techniques. As-deposited films are x-ray amorphous and are paramagnetic. Films annealed in air at temperatures Ta=400–750 °C develop a magnetic moment. The room-temperature magnetization M increases with Ta and shows a maximum for a specific Ta value which is a function of the nature and amount of the nonmagnetic substitution. With further increase in Ta, the observed decrease in M is accompanied by the onset of crystallization in the films. The largest saturation induction, 4πMs = 3.8 kG, is observed for samples substituted with 0.5 PbZrO3. The Curie temperatures are in the range 380–440 °C and are well below the crystallization temperature.