THERMAL-INDUCED DOMAIN PROCESSES IN TRIGLYCINE SULFATE CRYSTALS WITH CHROMIUM IMPURITIES

Abstract

The article presents the results of studies of thermally induced domain processes in chromium-containing crystals of triglycine sulfate (TGS). It is shown that a change in the temperature of TGS:Cr3+ crystals in the absence of external electric fields is accompanied by a rearrangement of the domain structure, that occurs most intensively in the region of the phase transition. A depolarizing field of ~1,4·10^5 V m-1, which is generated by a gradient change in the temperature of the sample, causes the process of switching its domain structure. In unannealed crystals at impurity concentrations exceeding 5·10^(-3) wt.%, switching processes are hindered, and the intensity of thermally induced domain processes is significantly lower than that for samples with a lower impurity content. The intensity of the switching processes of TGS:Cr3+ crystals is significantly influenced by the rate of their heating. The dependences of the integral number of polarization-reversal jumps on the heating rate of the samples N=f(V) are extreme. The extrema of the N=f(V) curves lie in the rate intervals (0,2-0,8) K·sec^(-1). The domain structure of TGS:Cr3+ crystals consists of a matrix of the main domain, lenticular and lamellar domains. Evolution of the domain structure is observed under the influence of an electron beam, accompanied by the growth of domains, their coalescence, and sample switching. High-temperature annealing of crystals leads to their polydomenization.

Keywords

• triglycine sulfate
• domain structure
• ligand
• switching processes
• annealing