Structure, ferromagnetism and microwave absorption properties of La substituted BiFeO3 nanoparticles

La substituted BiFeO3 nanoparticles were prepared by the sol-gel method. The effects of La on the structure, ferromagnetism and microwave absorpion properties of BiFeO3 at room temperature are investigated systematically. With 20 mol% La substitution, BiFeO3 undergoes a phase transformation from rhombohedral to pseudotetragonal structure, and its saturation magnetization enhances from 0.15 to 0.85 emu/g under the magnetic field of 20 kOe. The microwave absorption properties of BiFeO3 with La substitution is obviously enhanced in the frequency range from 8.2 to 12.4 GHz due to the improvement of electromagnetic match, and the maximum reflection loss reaches up to 30 dB, almost triple that of BiFeO3.