B site doping effect on depinning in Pb(Mn1/3Nb1/3Sb1/3)x(Zr0.825Ti0.175)1–xO3 ferroelectric ceramics

The polarization-field hysteresis (P-E) loops of Pb(Mn1/3Nb1/3Sb1/3)x(Zr0.825Ti0.175)1–xO3(PMnNSZT) ferroelectric ceramics show pinched shapes instead of the normal squarelike P-E loops in the range of 0.02≤x≤0.1. The pinched loops are assumed to be the result of the pinning effect of the defect dipoles. The absence of the pinched shape P-E loops can be attributed to the depinning resulting from strong p-type conductivity in PMnNSZT ceramics with high doping concentration of x>0.1. The x-ray photoelectron spectrum and x-ray diffraction investigations indicate that the p-type conductivity of the grain boundaries results from the aggregation of excessive B-site doping.