In Ba(Ti1- x Sn x )O3 solid solution, for Sn concentration x≤0.1, the permittivity follows the Curie-Weiss law above the Curie point T c. The increase in the peak value of the permittivity at T c is due to the change in ferroelectric transition from first order to second order with increasing x. For x>0.1, some deviations from the Curie-Weiss law are observed in a narrow temperature region above T c. The diffuse phase transition was observed. For x>0.2, the Curie-Weiss law does not hold over a wide temperature range. The dielectric dispersion was observed in the radio-frequency range (10 kHz–10 MHz). With increasing Sn concentration, the change in the phase transition from a normal ferroelectric transition to relaxor through the diffuse phase transition was observed.

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High-quality piezoelectric (1-x)Pb(In1/2Nb1/2)O3–xPbTiO3 binary system single crystals near a morphotropic phase boundary were successfully grown by a conventional flux method using PbO–PbF2–B2O3 flux. The largest crystal had dimensions of about 20 mm×10 mm×5 mm. The permittivity shows a shoulder at the ferroelectric rhombohedral to tetragonal phase transition temperature, T fr=100°C, and then has a maximum (35000 at 1 kHz) at the ferroelectric tetragonal to paraelectric cubic phase transition temperature, T c=260°C. The electromechanical coupling coefficient in rectangular bar mode, k 33 ′=78%, for phased array ultrasonic transducers was obtained by using the rhombohedral 0.72Pb(In1/2Nb1/2)O3–0.28PbTiO3 single crystal oriented along the [001] axis in the shape of a rectangular bar of 0.2 mm in width, 0.5 mm in thickness and 9 mm in length. The k 33 ′=78% is the highest value reported so far among all the piezoelectric materials with a T c more than 250°C.