Influence of defects and high temperature annealing on the kinetics of the transition to the antiferroelectric state in PbZr1-xTixO3 (Comunicazione a convegno)

Type
Label
  • Influence of defects and high temperature annealing on the kinetics of the transition to the antiferroelectric state in PbZr1-xTixO3 (Comunicazione a convegno) (literal)
Anno
  • 2014-01-01T00:00:00+01:00 (literal)
Alternative label
  • F. Cordero (1); F. Craciun (1); F. Trequattrini (2); C. Galassi (3) (2014)
    Influence of defects and high temperature annealing on the kinetics of the transition to the antiferroelectric state in PbZr1-xTixO3
    in Electroceramics XIV Conference, Bucarest, Romania, 16-20 June 2014
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • F. Cordero (1); F. Craciun (1); F. Trequattrini (2); C. Galassi (3) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • (1) CNR-ISC, ROma Tor Vergata (2) Dip. Fisica, Univ. Roma \"La Sapienza\" (3) CNR-ISTEC, Faenza (literal)
Titolo
  • Influence of defects and high temperature annealing on the kinetics of the transition to the antiferroelectric state in PbZr1-xTixO3 (literal)
Abstract
  • It has been known since a long time that the transition from the ferroelectric (FE) to the antiferroeletric (AFE) state in PZT may have extremely large thermal hysteresis and slow kinetics, attributed to the stabilisation of the FE phase by charged defects. Recent anelastic, dielectric and X-ray diffraction experiments on PZT with x = 0.05, near the morphotropic boundary with the FE phase, also demonstrated that the two components of the transformation, i.e. AFE ordering of the cation displacements and of the tilts of the O octahedra, may split and even produce a sharp tilt transition without AFE counterpart [2]. We present anelastic and dielectric measurements at compositions around 5% Ti showing that also the opposite instance occurs of an AFE component that is faster than the tilt one. In all cases, the anomalies of the elastic compliance versus temperature can be well fitted with the sum of broadened steps for each of the following transformations: 1) AFE cation, 2) tilt to the orthorhombic AFE phase and 3) tilt within the non-transformed rhombohedral FE phase. While the latter is always sharp and with small thermal hysteresis, the AFE transformations are sharp and coincident only during heating, but may have extremely large broadening and thermal hysteresis during cooling. The kinetics of these transitions becomes progressively slower with ageing but a prompt AFE transition is reobtained after annealing at >800 K. It is suggested that at the origin of this behaviour is the formation of ordered structures of O vacancies at the domain walls, which are dissolved only well above the Curie temperature. Such defects would be the cause of the intense thermally activated relaxation processes observed above TC in the dielectric and anelastic spectra (literal)
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