Glass behavior of a relaxor Cd2Nb2O7 in a weak DC field

Abstract

The temperature behavior of the dielectric response ehis(T) at a frequency of 1 kHz (110 K< T<300 K), δe(T)=[ehis(T)-eZFC(T)], and of the order parameter q(T), characterizing e(T) in a relaxor, is investigated for the relaxor Cd2Nb2O7 on samples with different thermal and electric histories in a dc field much weaker than the polarization saturation field. In a weak field (E dc=0.95 kV/cm), the behavior of δe(T) ∝ χnl changes in the region T f =184 K and the ehis(T) curves diverge monotonically at lower temperatures, indicating the development of the glassy state in the system. Analysis of the behavior of q(T) in the framework of the model of spin and dipole glasses shows that random interactions of polar microscopic regions in the presence of random fields play a dominating role in the phase formed below T f in the ZFC and FH/ZFC regimes. The relative contribution of random fields increases in the FC regime in a weak field and is manifested in the ZFH/FC regime both below and above T f .