Central peak and acoustic anomalies of the relaxor ferroelectric lead magnesium niobate-lead titanate single crystal studied by the micro-Brillouin scattering

Abstract

Quasielastic central peak and acoustic anomalies in a [001] lead magnesium niobate-lead titanate single crystal have been investigated by the high-resolution micro-Brillouin scattering. Two acoustic anomalies were observed at temperatures, TC-T∼415K and TT-R∼348K. The damping showed a significant dispersion at T∼550K, associated with the enhanced dynamics of local strain fields created by the polar microregions. The temperature evolution of the quasielastic central peak exhibited anomalies in the overall intensity and relaxation time that were associated with the line shape interferences of the central peak and the acoustic mode.

Anomalous behavior of acoustic phonon and central peak in Pb[(In1/2Nb1/2)0.65Ti0.35]O3 single crystal

“…In fact the appearance of narrow CP in PMN-PT system well below T B could be taken as the evidence for the existence of T ‫ء‬ . 14 In the present study also, the appearance of narrow CP and the coupling of the broad CP with LA phonon mode below T ‫ء‬ indeed support the existence of T ‫ء‬ where the longlived PNRs begin to form. The existence of T ‫ء‬ has also been established in another class of relaxor ferroelectric systems such as PST and PBST through Raman spectroscopic studies.…”

“…21 The dielectric studies on the composition near MPB show cubic-tetragonal ͑T ct ͒ and tetragonal-rhombohedral ͑T tr ͒ phase transitions that are similar to PMN-PT and PZN-PT systems. 14,22 However unlike PMN-PT and PZN-PT systems, the studies on the dynamical aspects of PNRs have not yet been carried out in PIN-PT solid solution system. Such studies on broader compositional system will help in the better understanding on the various physical aspects of PNRs.…”

“…[8][9][10] Extensive studies on the dynamical aspects of PNRs have been carried out in Pb͑Mg 1/3 Nb 2/3 ͒O 3 ͑PMN͒, Pb͑Zn 1/3 Nb 2/3 ͒O 3 ͑PZN͒, PMN-PT, PZN-PT, and Pb͑Ni 1/3 Nb 2/3 ͒O 3 ͑PNN͒-PT systems through neutron and light scattering studies. [11][12][13][14][15][16][17] Brillouin scattering studies in these systems clearly revealed interesting features of the PNRs, such as the softening of the acoustic phonon mode and the appearance of central peak ͑CP͒ below T B and slowing down of their relaxation time and the coupling between the polarization fluctuations and acoustic phonon modes. [14][15][16][17] Pb͑In 1/2 Nb 1/2 ͒O 3 ͑PIN͒ belongs to the class of Pb͑BЈBЉ͒O 3 compounds in which the degree of ordering of In 3+ and Nb 5+ ions can be altered by thermal treatment.…”

“…[11][12][13][14][15][16][17] Brillouin scattering studies in these systems clearly revealed interesting features of the PNRs, such as the softening of the acoustic phonon mode and the appearance of central peak ͑CP͒ below T B and slowing down of their relaxation time and the coupling between the polarization fluctuations and acoustic phonon modes. [14][15][16][17] Pb͑In 1/2 Nb 1/2 ͒O 3 ͑PIN͒ belongs to the class of Pb͑BЈBЉ͒O 3 compounds in which the degree of ordering of In 3+ and Nb 5+ ions can be altered by thermal treatment. Disordered PIN in which the B site is randomly occupied by In and Nb ions exhibits relaxor-type ferroelectric behavior.…”

Brillouin scattering studies of acoustic phonon modes and central peak in single-crystal Pb(Sc1/2Ta1/2)OSivasubramanian1, Kojima2 2012Phys. Rev. B

“…2 Extensive studies on the dynamical aspects of PNRs have been carried out in prototype RFEs such as Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) and other related systems through neutron and light scattering studies. [3][4][5][6][7][8][9] Brillouin scattering studies in these systems directly revealed the dynamical features of the PNRs such as the slowing down of their relaxation time and the coupling between the polarization fluctuations and acoustic phonon modes through the appearance of central peak (CP) and softening of the acoustic phonon mode. [6][7][8][9] This paper focuses on micro-Brillouin scattering studies on the dynamical aspects of PNRs in partially ordered Pb(Sc 1/2 Ta 1/2 )O 3 (PST) without any Pb vacancies.…”