Field-induced orientational percolation to a ferroelectric phase in relaxor Pb(In1/2Nb1/2)1-xTixO3

Abstract

This work presents direct observations of orientational percolation and depolarization in a (001)-cut relaxor Pb(In1∕2Nb1∕2)0.70Ti0.30O3 (PINT30%) crystal by means of dielectric permittivity, depolarization current, domain structure, and hysteresis loop. Electric (E)-field poling induced a 10–300μm size orientational percolation transition in the matrix. The percolation breaks down at depolarization temperature Td≅395K, which is ∼20–40K higher than in rhombohedral Pb(Mg1∕3Nb2∕3)1−xTixO3. Near 420K, the remaining polarization disappears, and the full relaxor-type dielectric dispersion due to polar nanoclusters reappears, and remains evident up to the Burns temperature TB≅520K. Under E=40kV∕cm at room temperature, small regions of [001] tetragonal domains appeared, but most of the crystal exhibited field-induced percolation rhombohedral and monoclinic microdomains embedded randomly in the matrix. This work suggests that this relaxor ferroelectric consists of two components (spherical glassy matrix and polar nanoclusters) as proposed for Pb(Mg1∕3Nb2∕3)O3 by Blinc et al. [Phys. Rev. Lett. 91, 247601 (2003)].