PHASE-TRANSITIONS AND GLASSLIKE BEHAVIOR IN SR1-XBAXTIO3

A dielectric and ultrasonic study of phase transitions in Sr1-xBaxTiO3 with x ranging from 0.0 to 1.0, is reported. Both ceramic samples and single crystals were studied. The full phase diagram is derived from dielectric measurements for ferroelectric phase transitions and from u ltrasonic measurements for structural phase transition. The cubic-tetr agonal ferroelectric phase transition which is of the first order in p ure BaTiO3 (x=1.0) transforms to the second order phase transition at x close to 0.2. The transition temperature T-c is a linear function of x at x values from 0.2 to 1.0. For x<0.2 the transition temperature i s proportional to (x-x(c))(1/2), where x(c)=0.035. For x<x(c) a glassl ike behavior is observed. The structural phase transition temperature T-a goes down as compared to pure SrTiO3 when x increases and levels o ff near x=0.05.