Freezing of dipole dynamics in relaxor ferroelectric Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-PbTiO<sub>3</sub> as evidenced by dielectric spectroscopy
A A Bokov; Z-G Ye; A A Bokov; A A Bokov; Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada; Z-G Ye; Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada; A A Bokov; Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
Журнал:
Journal of Physics: Condensed Matter
Дата:
2000-08-28
Аннотация:
Complex dielectric susceptibility (χ' + jχ'') has been studied at f = 10<sup>-2</sup>-10<sup>5</sup> Hz in the relaxor ferroelectric 0.75Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-0.25PbTiO<sub>3</sub>. In addition to the well known relaxor dispersion observed at temperatures around and below the temperature of permittivity maximum T<sub>m</sub>, a new and comparatively weak dispersion has been disclosed at T>T<sub>m</sub>. It is described by the `universal relaxation law', χ'' = cot(np/2)χ'∝f<sup>n-1</sup>. The temperature dependence of the exponent n follows the Vogel-Fulcher relation, indicating a process of freezing into the nonergodic state.
154.6Кб