Inelastic neutron scattering study of the relaxor ferroelectric PbMg1/3Nb2/3O3 at high temperatures

A. Naberezhnov; S. Vakhrushev; B. Dorner; D. Strauch; H. Moudden

doi:10.1007/s100510050912

2022 Impact factor 1.6

Condensed Matter and Complex Systems

Eur. Phys. J. B 11, 13-20 (1999)
https://doi.org/10.1007/s100510050912

Inelastic neutron scattering study of the relaxor ferroelectric PbMg_1/3Nb_2/3O₃ at high temperatures

A. Naberezhnov¹^a, S. Vakhrushev¹, B. Dorner², D. Strauch³^b and H. Moudden⁴

¹ Ioffe Phys.-Tech. Institute, 26 Politekhnicheskaya, 194021 St.-Petersburg, Russia
² Institut Laue-Langevin, B.P. 156, 38042 Grenoble Cedex 9, France
³ Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany
⁴ Laboratoire Léon Brillouin (CEA-CNRS), CEA Saclay, 91191 Gif-sur-Yvette Cedex, France

Corresponding authors: ^a s.vakhrushev@shuvpop.ioffe.rssi.ru - ^b dieter.strauch@physik.uni-regensburg.de

Received: 8 February 1999
Published online: 15 September 1999

Abstract

Results of inelastic neutron scattering experiments between 300 K and 900 K on the relaxor ferroelectric PbMg_1/3Nb_2/3O₃ are presented. Within a mode-coupling analysis the data are consistent with the observation of a strongly damped quasi-optic excitation. It is demonstrated that below K a dynamical crossover takes place manifesting itself by a narrow central peak. This crossover is accompanied by the appearance of strong damping of the transverse acoustic phonons, with the damping constant proportional to q⁴. Different physical models of the crossover are discussed.