PLZT Phases Near Lead Zirconate: 1. Determination by X-Ray Diffraction |
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Authors: | Else Breval Chiping Wang Joseph P Dougherty Kamau wa Gachigi |
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Affiliation: | Materials Research Institute, Penn State University, University Park, Pennsylvania 16802; Department of Mechanical Engineering, University of Nairobi, Nairobi, Kenya |
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Abstract: | The room temperature phase diagram of PLZT, (Pb,La)(Zr,Ti)O3, 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%, La2Zr2O7 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. |
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