Dynamic characteristics of defect dipoles in Mn-doped 0.24Pb(In _1/2 Nb _1/2 )O ₃ -0.47Pb(Mg _1/3 Nb _2/3 )O ₃ -0.29PbTiO ₃ single crystal

The dynamic ferroelectric hysteresis loops with internal bias field were investigated in poled and aged Mn-doped 0.24Pb(In _1/2 Nb _1/2 )O ₃ -0.47Pb(Mg _1/3 Nb _2/3 )O ₃ -0.29PbTiO ₃ single crystal. Below the normal-relaxor transition temperature T _nr , asymmetric hysteresis loops along the electric field axis were observed at high frequencies, whereas normal square-like loops were found at low frequencies (<0.1 Hz). When T > T _nr , slim P-E loops appear and the macroscopic ferroelectric properties disappear due to the presence of polar nanoregions (PNRs). The strong temperature and frequency dependence of the internal bias field is believed to be correlated with the defect dipole reorientation induced by both the electric field and thermal activation. Intriguingly, polynomial scaling relations with temperature T and stretched exponential time t (reciprocal of frequency) were established for the internal bias field in the form of E _i (T) = AT ² + BT + C and E _i (t) = E _i0 exp[-(t/τ) ⁿ ] below the rhombohedral-tetragonal transition temperature (T _R-T ). These results provide a deeper understanding on the movement mechanisms of defect dipoles in acceptor-doped ferroelectrics.