Direct evidence of soft mode behavior near the Burns' temperature in PbMg₁ / ₃Nb₂ / ₃O₃ (PMN) relaxor ferroectric

الأصل · EN

Inelastic neutron scattering measurements of the relaxor ferroelectric PbMg₁ / ₃Nb₂ / ₃O₃ (PMN) in the temperature range 490 K<T<880 K directly observe the soft mode (SM) associated with the Curie-Weiss behavior of the dielectric constant ε (T). The results are treated within the framework of the coupled SM and transverse optic (TO1) mode and the temperature dependence of the SM frequency at q=0.075 a* is determined. The parameters of the SM are consistent with the earlier estimates and the frequency exhibits a minimum near the Burns temperature (≈ 650K)