Frequency dependence of the coercive field of 0.71 Pb(Mg_(1/3)Nb_(2/3)) O_3-0.29PbTiO_3 single crystal from 0.01 Hz to 5 MHz

摘要

The frequency dependence of the coercive field E_c in [001]_c poled 0.71Pb(Mg_(1/3)Nb_(2/3))O_3-0.29PbTiO_3 single crystals was investigated as a function of frequency /from 0.01 Hz to 5 MHz. E_c was found to be proportional to f~β as predicted by the Ishibashi and Orihara model, but our results showed two frequency regimes separated at around 1.0 MHz with different β values. This change of switching kinetics may be due to the presence of slower relaxation times for non-1800 domain switching and heterogeneous nucleation of polar nanoregions, whose contribution to polarization reversal is frozen out beyond 1.0 MHz, leading to a larger β.