Effect of substrates on magnetization of BiFeO3 films

BiFeO3 (BFO) films were fabricated on Pt/Ti/SiO2/Si and single crystalline LiNbO3 (LN) substrates using metal organic decomposition method and annealed in N2/O2. Magnetizations of these films were systematically characterized. It is found that BFO films prepared on Pt/Ti/SiO2/Si substrates exhibit stronger saturation magnetization (MS) than those prepared on LN substrates, and their magnetizations rely more on annealing atmosphere. We consider that both oxide feature of LN substrates and in-plane compressive stress introduced by LN reduce the Fe2+ content in the top BFO films and further stabilize the films against post-treatment. This work provides a valuable guidance for fabricating high quality magnetic oxide films.