High-pressure phase transitions in BiFeO3: hydrostatic vs. non-hydrostatic conditions

TL;DR

This study investigates how hydrostatic and non-hydrostatic pressure conditions affect phase transitions in BiFeO3, revealing the material's high sensitivity to stress and implications for interpreting high-pressure experiments.

Contribution

The paper compares high-pressure phase transitions in BiFeO3 under different stress conditions, highlighting the impact of non-hydrostatic stress on structural changes.

Findings

Different phase transition pathways under hydrostatic and non-hydrostatic conditions

BiFeO3 is highly sensitive to non-hydrostatic stress

Implications for high-pressure structural analysis

Abstract

We report high-pressure x-ray diffraction experiments on BiFeO3 (BFO) single crystals in diamond-anvil cells up to 14 GPa. Two data sets are compared, one in hydrostatic conditions, with helium used as pressure-transmitting medium, and the other in non-hydrostatic conditions, with silicon oil as pressure-transmitting medium. It is shown that the crystal undergoes different phase transitions in the two cases, highlighting the high sensitivity of BFO to non-hydrostatic stress. Consequences for the interpretation of high-pressure structural studies are discussed.