Temperature–field phase diagram and spontaneous polarization in Pb(Sc_1/2Ta_1/2)O₃ single crystal

Abstract

The temperature–field phase diagram and the temperature dependence of the spontaneous polarization in Pb(Sc1/2Ta1/2)O3 (PST) have been investigated by measuring the permittivity in the dc biasing field and observing the p–E hysteresis loop, respectively. X-ray diffraction studies to clarify the B-site cation ordering have also been performed. We have confirmed the PST single crystal used in our experiment to be a disordered PST. We have also determined that the ferroelectric critical endpoint (CEP) on the temperature–field phase diagram in the dc biasing field applied along the [111]c direction (in the cubic coordinate) was at 19.3 °C and 4.85 kV cm−1. Our experimental results of the ferroelectric CEP and the spontaneous polarization in disordered PST are discussed in this paper on the basis of the Landau-type phenomenological theory.

Double hysteresis loops and temperature–field phase diagram in Pb(Mg1/3Nb2/3)O3–29.5%PbTiO3

“…In PMN-29.5%PT, the slope of the phase boundary at E = 0 is reduced to be 0.193 kV cm −1 K −1 . The common property of the perovskite-type ferroelectrics such as PMN-PT reported in this paper and PZN-PT and PST reported earlier 32,34) is that the critical field is small around 1 kV cm −1 . This indicates that the phase transition in these materials is a first-order phase transition very close to the second order, or very close to the tricritical point.…”

“…/ respectively. 33,34) The temperature at which the transition field in the field decreasing process becomes zero is reduced to a…”

“…(1), using the four experimental values of T W (134.4 °C), the critical temperature T CEP (138.5 °C), the critical field E CEP (1.2 kV cm −1 ), and the temperature dependence of the spontaneous polarization. From the temperature α W and critical temperature α CEP , we obtain the relational expression 34) a a…”

“…33) So far, it has been shown that the ferroelectric CEP appears in a small electric field around 1 kV cm −1 in the Perovskitetype ferroelectrics such as PZN-xPT and PST. 32,34) Existence of CEP in PMN-29.5%PT should be confirmed to be more certain, although it was determined from the permittivity measurement under a DC biasing field. 31) Therefore, it is worth demonstrating the existence of CEP in PMN by another experimental method.…”

Enhanced Electrocaloric Effect of Lead Scandium Tantalate by Zirconium Doping

“…Lead scandium tantalate (PbSc 0.5 Ta 0.5 O 3 , PST) is a perovskite ferroelectric material with two types of ions, Sc 3+ and Ta 5+ , occupying the B-site, which contributes to its unique characteristics. , It exhibits remarkable pyroelectric properties near room temperature and is widely used in infrared detection, thermal imaging, and energy harvesting . Due to the inverse relationship between the ECE and the pyroelectric effect, PST shows great potential for electrocaloric cooling applications in the near-room temperature range.…”