Re-entrant phenomenon in diffuse ferroelectric, $BaSn_{0.15}Ti_{0.85}O_{3}$ : Local structural insights and FORC study

TL;DR

This study investigates the re-entrant ferroelectric behavior in BaSn0.15Ti0.85O3 near room temperature, combining dielectric, polarization, FORC, and local structural analyses to understand its relaxor properties and local environment changes.

Contribution

It provides new insights into the local structural changes and re-entrant phase behavior in BaSn0.15Ti0.85O3 using combined electrical and spectroscopic techniques.

Findings

Re-entrant phase observed at low temperatures.

Dielectric constant shows frequency dispersion near T_C.

Local probes reveal structural environment changes.

Abstract

From the phase diagram as proposed by Lei et.al., [J. App. Phys 101, 084105 (2007)] a $BaSn_{0.15}Ti_{0.85}O_{3}$ is chosen showing a diffuse phase transition between cubic to rhombohedral (C-R) near room temperature. Dielectric analysis confirms a phase transition near room temperature ($T_{C}$ $\approx$ 290 K) and also frequency dispersion in dielectric constant is observed towards low temperature. Polarization and first-order reversal curves (FORC) suggest that the system is in re-entrant phase at low temperatures. Put together, all these electrical characterization results points toward the relaxor behavior in the re-entrant phase. Local probe techniques such as x-ray absorption near edge spectroscopy, Raman and Mossbauer spectroscopy are employed to investigate the local environment changes around this region of low temperature dielectric anomaly. A simple ferroelectric exchange model explaining the low temperature re-entrant behavior is presented from these results.