X-ray and neutron scattering

Research group

Research theme

Sub department

About

Phonon dispersion relations in PrBa2 Cu3 Q 6+x (x ≈ 0.2)

Physical Review B - Condensed Matter and Materials Physics 69:9 (2004) 923021-923024

Authors:

CH Gardiner, AT Boothroyd, BH Larsen, W Reichardt, AA Zhokhov, NH Andersen, SJS Lister, AR Wildes

Abstract:

We report measurements of the phonon dispersion relations in nonsuperconducting, oxygen-deficient PrBa2Cu3O 6+x (x ≈ 0.2) by inelastic neutron scattering. The data are compared with a model of the lattice dynamics based on a common interatomic potential. Good agreement is achieved for all but two phonon branches, which are significantly softer than predicted. These modes are found to arise predominantly from motion of the oxygen ions in the CuO2 planes. Analogous modes in YBa2Cu3O6 are well described by the common interatomic potential model.

Automatic determination of the morphotropic phase boundary in lead magnesium niobate titanate Pb(Mg1/3Nb2/3)(1-x)TixO3 within a single crystal using birefringence imaging

JOURNAL OF APPLIED CRYSTALLOGRAPHY 37 (2004) 143-149

Authors:

D Zekria, AM Glazer
More details from the publisher

Birefringence of lead titanate (PbTiO3)

JOURNAL OF APPLIED CRYSTALLOGRAPHY 37 (2004) 551-554

Authors:

D Zekria, AM Glazer, V Shuvaeva, J Dec, S Miga
More details from the publisher

Diffuse first-order phase transition in NaNbO3:Gd

JOURNAL OF PHYSICS-CONDENSED MATTER 16:15 (2004) PII S0953-8984(04)77241-0

Authors:

IP Raevski, SI Raevskaya, SA Prosandeev, VA Shuvaeva, AM Glazer, MS Prosandeeva
More details from the publisher

Effect of high pressure on the relaxor ferroelectrics Na1/2Bi1/2TiO3 (NBT) and PbMg(1/3)Nb(2/3)O3 (PMN)

FERROELECTRICS 302 (2004) 539-544

Authors:

J Kreisel, P Bouvier, B Dkhil, B Chaabane, AM Glazer, PA Thomas, TR Welberry

Abstract:

The aim of the present paper is to review and briefly discuss recent experimental results on the effect of high pressure (p > 1.5 GPa) on relaxor ferroelectrics, exemplified by Na1/2Bi1/2TiO3 and PbMg1/3Nb2/3O3. The main result is that relaxor ferroelectrics present important polar and structural pressure-instabilities, which lead to both phase transitions of the average structure and considerable changes of the local structure. It is in particular the observation of a pressure-induced suppression of the relaxor characteristic X-ray diffuse scattering that points to important changes in the local order. The complementary use of Raman spectroscopy, X-ray diffraction and X-ray diffuse scattering allows the proposition of a mechanism for the observed changes.
More details from the publisher