Origin and stability of the dipolar response in a family of tetragonal tungsten bronze relaxors

Andrei Rotaru, Donna C. Arnold, Aziz Daoud-Aladine, Finlay D. Morrison

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)

Abstract

A new family of relaxor dielectrics with the tetragonal tungsten bronze structure ( nominal composition Ba6M3+Nb9O30, M3+ = Ga, Sc, or In) were studied using dielectric spectroscopy to probe the dynamic dipole response and correlate this with the crystal structure as determined from powder neutron diffraction. Independent analyses of real and imaginary parts of the complex dielectric function were used to determine characteristic temperature parameters, T-VF and T-UDR, respectively. In each composition both these temperatures correlated with the temperature of maximum crystallographic strain, T-c/a, determined from diffraction data. The overall behavior is consistent with dipole freezing and the data indicate that the dipole stability increases with increasing M3+ cation size as a result of increased tetragonality of the unit cell. Crystallographic data suggests that these materials are uniaxial relaxors with the dipole moment predominantly restricted to the B1 cation site in the structure. Possible origins of the relaxor behavior are discussed.

Original languageEnglish
Article number184302
Number of pages12
JournalPhysical Review. B, Condensed matter and materials physics
Volume83
Issue number18
DOIs
Publication statusPublished - 31 May 2011

Keywords

  • GLASSY POLARIZATION BEHAVIOR
  • LEAD MAGNESIUM NIOBATE
  • FERROELECTRIC PROPERTIES
  • DIELECTRIC-PROPERTIES
  • NEUTRON-DIFFRACTION
  • CRYSTAL STRUCTURES
  • PHASE-TRANSITION
  • CUBIC PHASE
  • THIN-FILMS
  • CERAMICS

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