Non-Debye dielectric dispersion of barium titanate stannate in the relaxor and diffuse phase-transition state

Abstract

Frequency dependence Tm(f ) of the permittivity maximum temperature observed in BaTi1−xSnx03, x=0.2 (BTS20), confirms that this composition is close above threshold xc for relaxor behavior in BTS. The low-frequency permittivity carries a ln(1/f )-frequency dependence in the vicinity of Tm, both for x=0.2 and x=0.125<xc. At temperatures T<Tm, the non-Debye contribution of both compositions shows a qualitatively different temperature dependence, indicating basic differences between the diffuse phase-transition state and the relaxor state of BTS.