Enhanced multiferroic properties of Aurivillius Bi_6Fe_(1.4)Co_(0.6)Ti_3O_(18) thin films by magnetic field annealing

摘要

We investigate the effect of high magnetic-field annealing on the microstructural, ferroelectric, and magnetic properties of Bi_6Fe_(1.4)Co_(0.6)Ti_3O_(18) thin films. The magnetic field can lower the energy barrier for nucleation and improve the grain connectivity. The application of magnetic field of 6T parallel to the film plane can substantially enhance the remnant polarization P_r from 18.1 to 29 μC/cm~2 as a result of the variation in grain size and growth orientation caused by magnetic field annealing. Moreover, the remnant magnetization M_r is substantially improved from 2.48 to 4.56 emu/cm~3 arising from the enhanced exchange coupling due to the better grain connectivity. These results demonstrate that high magnetic-field annealing is an effective way to optimize multiferroic properties of the Aurivillius compounds.