A structural model for the relaxor PbMg<sub>1/3</sub>Nb<sub>2/3</sub>O<sub>3</sub> at 5 K
N de Mathan; E Husson; G Calvarn; J R Gavarri; A W Hewat; A Morell; N de Mathan; Lab. de Chimie Phys. du Solide, Ecole Centrale de Paris, Chatenay-Malabry, France; E Husson; Lab. de Chimie Phys. du Solide, Ecole Centrale de Paris, Chatenay-Malabry, France; G Calvarn; Lab. de Chimie Phys. du Solide, Ecole Centrale de Paris, Chatenay-Malabry, France; J R Gavarri; Lab. de Chimie Phys. du Solide, Ecole Centrale de Paris, Chatenay-Malabry, France; A W Hewat; Lab. de Chimie Phys. du Solide, Ecole Centrale de Paris, Chatenay-Malabry, France; A Morell; Lab. de Chimie Phys. du Solide, Ecole Centrale de Paris, Chatenay-Malabry, France
Журнал:
Journal of Physics: Condensed Matter
Дата:
1991-10-21
Аннотация:
The perovskite structure of the relaxor PbMg<sub>1/3</sub>Nb<sub>2/3</sub>O<sub>3</sub> (PMN) is studied using X-ray and neutron powder diffraction data. The static diffuse scattering (SDS) observed in the diffraction patterns at low temperatures is interpreted using a two-phase Rietveld analysis. The structural model is based on a long-range structure with an average cubic symmetry, and a short-range order due to atomic shifts involved by the formation of polar regions. The two-phase model provides a good improvement in reliability factors. The correlation length and the coexistence of different phases at low temperatures are discussed.
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