Ultrasound Pulse Echo Study of KLT

We explore the development of relaxor ferroelectric order in single crystals of K_1-x1Li_iTaO₃(KLT) with x = 0.01, 0.1, 0.2. The phase transitions occur upon cooling the crystal either spontaneously or under an electric field. We probe the sample by sending 1 µs-long 30 MHz ultrasound probe pulses and receiving their echoes. From this, we obtain the temperature dependence of speed and attenuation of ultrasound, i.e., information on elastic properties and polar clusters structure. The details of the experiment and current results are presented. Our goal is, through a comprehensive study of the elastic properties of this relatively simple material, to develop a model of the relaxor ferroelectric transitions that would be applicable to more complicated compounds.