PLZT Phases Near Lead Zirconate: 1. Determination by X‐Ray Diffraction

Abstract

The room temperature phase diagram of PLZT, (Pb,La)(Zr,Ti)O 3 , or L / Z / T for L <12 and T <10 was constructed using X‐ray diffraction patterns of sintered and crushed PLZT material. The orthorhombic antiferroelectric phase, a tetragonal phase, the rhombohedral (hexagonal) ferroelectric phases, and the mixed La‐rich zone were identified. Increasing substitution of La for Pb in the structure of orthorhombic PLZT leads to a change toward the cubic structure with less anisotropy in a direction corresponding to the cubic 200 direction. At La above ∼8 to 11 mol%, La 2 Zr 2 O 7 appears in the mixed zone. With increasing substitution of Ti for Zr, there is no change toward a cubic structure as the anisotropy is nearly unchanged. However, at a Ti substitution above ∼6 mol%, a rhombohedral and a tetragonal structure appear.