The effect of thickness-dependent strain relaxation on magnetoelectric behaviors for highly c-axis oriented BiFeO3 films on Si substrate

Abstract The thickness-dependent strain-relaxation behavior and the associated impacts upon the magnetic, electric properties and magnetoelectric coulpling effect for the highly c-axis oriented BiFeO3 (BFO) film films grown on (001) oriented Si substrate were studied. The result shown that the value of remnant polarization and coercive field were suppressed as the strain relaxes with increasing thickness. The BFO films also presented typical weak ferromagnetic hysteresis loops with a low coercive field and small remnant magnetization, and the saturated magnetization and remnant magnetization decreasing with increasing film thickness. The room temperature dynamic magnetoelectric coupling was approved by the transverse magnetoelectric voltage coefficients, which also decreased with strain relaxation due to the increase of thickness, and the maximum was around 265mV/cm.Oe when the film thickness is 50 nm.