Polar and nonpolar atomic motions in the relaxor ferroelectric Pb1-3x/2LaxZr0.2Ti0.8O3 from dielectric, anelastic, and NMR relaxation

Cordero F., Corti M., Craciun F., Galassi C., Piazza D., Tabak F.

PHYSICAL REVIEW B, vol.71, no.9, 2005 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 71 Issue: 9
  • Publication Date: 2005
  • Doi Number: 10.1103/physrevb.71.094112
  • Journal Name: PHYSICAL REVIEW B
  • Journal Indexes: Science Citation Index Expanded, Scopus

Abstract

Dielectric, anelastic, and La-139 NMR relaxation measurements have been made on the relaxor ferroelectric Pb1-3x/2La.Zr0.2Ti0.8O3 (PLZT) with x=0.22. The dielectric susceptibility exhibits the frequency dispersive maximum due to the freezing of the polar degrees of freedom around T 250 K. The anelastic and especially NMR relaxation, besides this maximum, indicate an intense and broad component at lower temperatures, attributed to rotational modes of the O octahedra, weakly coupled to the polar modes. It is discussed why such short range rotational instabilities, known to occur in the Zr-rich rhombohedral region of the PLZT phase diagram, might appear also in the Ti-rich region.