Impact of annealing atmosphere on the multiferroic and dielectric properties of BiFeO_3/Bi_(3.25)La_(0.75)Ti_3O_(12) thin films

摘要

Multiferroic BiFeO_3/Bi_(3.25)La_(0.75)Ti_3O_(12) films annealed in different atmospheres (N_2 or O_2) were prepared on PtATi/SiO2/Si substrates via a metal organic decomposition method. Based on our experimental results, it is considered that, in the films annealed in N_2, fewer Fe~(2+) ions while more oxygen vacancies are involved. As a result, at room temperature, predominated by the reduced Fe~(2+) fraction, lower leakage current and dielectric loss, better ferroelectric property while reduced magnetization are observed. However, the oxygen vacancies might be thermally activated at elevated temperature; thus, more strongly temperature-dependent leakage current and a higher dielectric relaxation peak are observed for the films annealed in N_2.