High dielectric tunability, electrostriction strain and electrocaloric strength at a tricritical point of tetragonal, rhombohedral and pseudocubic phases

Abstract

High dielectric tunability, electrostriction strain and electrocaloric strength at a tricritical point of tetragonal, rhombohedral and pseudocubic phases, Journal of Alloys and Compounds (2015), Abstract A relaxor ferroelectric Pb(Ni 1/3 Nb 2/3 ) 0.5 Zr 0.15 Ti 0.35 O 3 (PNNZT) ceramic was reported, designed upon an idea that the composition is selected to near a tricritical point of tetragonal, rhombohedral and pseudocubic phases. High dielectric tunability of 67%, A C C E P T E D ACCEPTED MANUSCRIPT 2 simultaneously with high electrostriction strain of 0.319% and high electrocaloric strength (∆T/∆E) of 32.5 mK cm/kV are achieved, which make it a promising multifunctional material for applications in dielectric tunable, precisely controlled and electric refrigeration devices. This is endowed by the low energy barrier among the transitions of phases and strong relaxor ferroelectric activities around the tricritical point. This work provides a guide for the design of multifunctional ferroelectric materials and can promote the development of other multifunctional ferroic materials.

Phase-transition induced giant negative electrocaloric effect in a lead-free relaxor ferroelectric thin film

“…[10,11,13] However, the T and S peaks in positive effect shift to higher temperatures with increasing electric field, as reported by previous experimental and theoretical works. [38,39] The maximum T which is near the right part of the δorentz extrapolated peak (TA) (see Fig. 3(a)) of dielectric permittivity is about -42.5 K at ~ 163 C and at 1632 kVcm -1, and the corresponding S is about -29.3 JK -1 kg -1 .…”

Large electrocaloric responses in [Bi1/2(Na,K)1/2]TiO3‐based ceramics with giant electro‐strains

“…Thus, there could be all three types of phase transitions in our materials. It is believed that the combination of mechanisms benefits electrocaloric and electromechanical responses simultaneously . In order to verify the mechanism of large electrocaloric response, especially in BNKT‐2.5Nb, we conducted in situ TEM study (Figure ).…”

“…It is believed that the combination of mechanisms benefits electrocaloric and electromechanical responses simultaneously. 41 In order to verify the mechanism of large electrocaloric response, especially in BNKT-2.5Nb, we conducted in situ TEM study (Figure 7). At virgin state ( Figure 7A), the grain is occupied with nanometer-sized domains.…”

Phase-transition induced optimization of electrostrain, electrocaloric refrigeration and energy storage of LiNbO3 doped BNT-BT ceramics

“…Piezoceramics are a kind of very important functional materials, which have been applied in every corner of human life and production [1][2][3]. Traditional piezoelectric ceramics are mainly PbZrTiO3 (PZT) based binary and ternary ceramics with a series of excellent properties [4,5]. However, these PZT-based piezoelectric ceramics emit toxic substances in the process of preparation and use, causing harm to human body and environment.…”