Composition-Related Dielectric, Ferroelectric and Electrocaloric Properties of Pb5Ge3O11 Single Crystals Modified by Ba Ions

Abstract

In this paper, we studied some ferroelectric properties of archetypal oxide uniaxial ferroelectric single crystals of Pb5Ge3O11 modified by Ba ions. They include dielectric, DSC, ferroelectric polarization, and electrocaloric effect (ECE) measurements. The measurements show that increasing Ba doping considerably influences all the measured parameters, mainly by lowering the Curie temperature, gradually diffusing the phase transition, and decreasing values of polarization as well as the coercive field. The decrease in overall ECE is influenced by decreasing polarization. Compared with the pure PGO single crystals, this decrease is from 1.2 K to 0.2 K. However, the effect of diffusing the phase transition increases the range of its occurrence (up to 30 K), which might be beneficial in applications.

Crystallographic, Structural, and Electrical Properties of W6+ Substituted with Mo6+ in Crystalline Phases such as TTB Structure

“…Other experimental research on TTB-structured ferroelectric materials, with Ba 2(1−x) Pb 2.05x Na 1−0.1x Nb 5 O 15 and Pb 2(1−x) Gd x K 1+x Nb 5 O 15 , has been conducted [59][60][61][62]. In it, this process was explained by changes in the polarization axis, which can also occur in the solution investigated in this work, as well as reorientation of dipoles [55].…”

“…Figure 6a-d de variation of the opposite dielectric permittivity versus temperature during heati frequency of 1 kHz. The shape of the curve for all of the compositions follow Curie-Weiss law well in the paraelectric phase defined by equation 4 [55]:…”