Thermal hysteresis of dielectric response in lead scandium tantalate ceramics

Lead scandium tantalate (PST) is a ferroelectric relaxor with the perovskite structure of A(B\´B")O₃. An anomalously large thermal hysteresis in the dielectric response was found for the mostly disordered PST ceramic. The degree of the hysteresis decreased with increased ordering. The mostly ordered PST ceramics exhibited a typical thermal hysteresis in dielectric response like the normal ferroelectric that forms macrodomains at the transition temperature. The large dielectric hysteresis found in the mostly disordered PST is ascribed to the microdomain-macrodomain transition, which probably occurs when a critical interaction level is reached between microdomains