Temperature-driven evolution of hierarchical nanodomain structure in tetragonal-like BiFeO3 films

TL;DR

This study uncovers a temperature-dependent hierarchical nanodomain structure in tetragonal-like BiFeO3 films, showing reversible phase transitions and detailed nanostructure evolution through electron microscopy.

Contribution

It reports the first observation of a hierarchical nanodomain structure in BiFeO3 films and its reversible transformation with temperature changes.

Findings

Hierarchical nanodomain structure with lamellar substructure

Reversible transition to tweed-like domains near 120°C

First-order phase transition with thermal hysteresis

Abstract

Transmission electron microscopy study of tetragonal-like BiFeO3 films reveals a hitherto unreported hierarchical nanodomain structure. The 30-50 nm wide stripe domains with {110} domain walls consist of a substructure of lamellar nanodomains of 8-10 nm width in a herringbone-like arrangement. In situ heating and cooling reveals a reversible transition from the hierarchical nanodomain structure to a tweed-like domain structure which is accompanied by a first-order phase transition near 120 {\deg}C with a thermal hysteresis.