Elastic properties of K_1-xLi_xTaO₃ (KLT) Ferroelectric Relaxor Crystals studied by Resonant Ultrasound Spectroscopy (RUS).

Single-crystalline KLT is a rather under-investigated material. However, it represents a relatively simple model for relaxor ferroelectricity phenomenon; its optical transparency makes it a candidate for photonics applications. We report the results of our study of temperature dependences of elastic stiffness tensor parameters for a set of crystals with x = 0.01, 0.1, and 0.2 at temperatures ranging from room down to 80K. Anomalous softening of these parameters reveal the temperatures at which the phase transition occurs, so-called Curie temperatures T_c, where the unique properties of the material are most prominent. We found T_c to vary with the concentration of lithium. At x = 0.2, the T_c was estimated at 150K and at x = 0.1 the T_c was about 120K. At x = 0.01 the Tc fell below 80K, which requires further study.