Evolution from relaxor-like dielectric to ferroelectric in Ba[(Fe0.5Nb0.5)1−xTix]O3 solid solutions

Ba[(Fe0.5Nb0.5)1−xTix]O3 (x=0.2,0.4,0.6,0.8,0.85,0.9x=0.2,0.4,0.6,0.8,0.85,0.9 and 0.95) solid solutions were synthesized by a standard solid-state reaction technique. X-ray diffraction at room temperature and dielectric characteristics over a broad temperature and frequency range were evaluated systematically. The structure of Ba[(Fe0.5Nb0.5)1−xTix]O3 solid solutions changed from cubic to tetragonal with increasing xx. A Debye-like dielectric relaxation following the Arrhenius law similar to that in Ba(Fe0.5Nb0.5)O3 was observed at lower temperature in the composition range 0.2≤x≤0.80.2≤x≤0.8, while the relaxor ferroelectric, diffused ferroelectric and normal ferroelectric behavior were observed for x=0.85,0.9x=0.85,0.9 and 0.95, respectively. The process of the evolution of relaxor-like dielectric to ferroelectric suggested the changing from dilute polar micro-domains to polar micro-domains, polar micro/macro-domains and then polar macro-domains in the present ceramics.

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► Solid solution forms in Ba[(Fe0.5Nb0.5)1−xTix]O3.
► Crystal structure changes from cubic to tetragonal.
► Dielectric nature changes from relaxor-like dielectric to relaxor ferroelectric, defuse ferroelectric, and finally normal ferroelectric.