Phase transitions of pure and Ba-doped BiFeO3 under high pressure

In order to evaluate the effect of impurity substitution on phase transition of BFO, we report high-pressure X-ray diffraction experiments on pure and Ba-doped BiFeO3 powders in diamond-anvil cells up to 18.7 GPa. A low-temperature hydrothermal synthesis route was utilized to fabricate these two samples. The experimental results reveal that two structural phase transitions take place in these two different samples in the investigated pressure range. As two ADXRD data sets are compared, it is shown that the intermediate phase II is not detected in Ba-doped sample. In addition, modifications in phase transition behavior and compressibility due to a minor Ba incorporation highlight the high sensitivity of BFO to variations of chemical composition.

► The phase transitions of pure and Ba-doped BiFeO3 under high pressure. ► The Ba incorporation causes a modification of the transition sequence. ► The difference in bulk modulus of R3c could be attributed to the size-induced effect.