LAUSR

In this paper, the frequency (f) behavior of hysteresis loops in a tetragonal Mn:Fe:KTN crystal is investigated. We have found that the shape of P–E hysteresis loops experiences systemic f-dependent changes from an asymmetric double hysteresis loop to a normal single loop, as the frequency changes from high to low (150–0.01 Hz). The shape of P–E loop is strongly f-dependent only at low frequency (f < 1 Hz) and f-independent at the high one (f ≥ 10 Hz), and the maximum polarization stays unchanged with f varying at the same temperature and amplitude of electric field. The frequency-dependent properties of hysteresis loop stem from the forced vibration of two types of electric dipoles induced by the off-center displacement and the local composition gradient distribution, with different response time to applied electric field. The results are of great value for enhancing device performance and fabricating required devices with specific performance characteristics.