Studies on dielectric relaxation in ceramic multiferroic Gd1-xYxMnO3
arXiv:1706.08706 · doi:10.1111/jace.14758
Abstract
Dielectric study over a broadband was carried out from 10 to 70 K on ceramic Gd1-xYxMnO3 (x= 0.2, 0.3, and 0.4). For all the compositions, a prominent sharp peak about ~18K was observed in the temperature dependence of both ε'(T) and ε"(T) at all frequencies, indicating a long-range ferroelectric (FE) transition. Using Cole-Cole fit to the permittivity data, the relaxation time τ and the dielectric strength Δε were estimated. Temperature variation of τ(T) in the Arrhenius representation is found to be nonlinear (non-Debyean relaxation), with increasing barrier-activation energy over successive temperature-windows. Interestingly, for all the compositions, we witness a jump in τ(T) about the ferroelectric transition temperature, concurred by a broad-maximum in Δε(T), signifying the critical slowdown of relaxations near long-range FE-correlations.
20 Pages, 10 Figures, 1 Table, and 14 References