ISSN:
1434-6036
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Physik
Notizen:
Abstract. Neutron scattering investigations were carried out in PbMg1/3Ta2/3O3 and BaMg1/3Ta2/3O3 complex perovskites. The crystal structure of neither compound shows any phase transition in the temperature range 1.5-730 K. Whereas the temperature dependence of the lattice parameter of BaMg1/3Ta2/3O3 follows the classical expectations, the lattice parameter of relaxor ferroelectric PbMg1/3Ta2/3O3 exhibits anomalies. One of these anomalies is observed in the same temperature range as the peak in the dielectric susceptibility. Below $T\sim180$ K PbMg1/3Ta2/3O3 exhibits very small thermal expansion, similar to invar alloys. We find that in PbMg1/3Ta2/3O3, lead ions are displaced from the ideal positions in the perovskite structure at all temperatures. Consequently short-range order is present. This induces strong diffuse scattering with an anisotropic shape in wavevector space. The temperature dependences of the diffuse neutron scattering intensity and of the amplitude of the lead displacements are similar.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1140/epjb/e2004-00276-8
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