Pressure-induced ferroelectric-relaxor phase transition in (Bi0.5Na0.5)TiO3-based ceramics

In this work, the effects of composition, temperature, and poling on the phase transition behavior under hydrostatic pressure of lead-free (1-x)[(0.98Bi(0.5)Na(0.5)Ti(0.995)Mn(0.005)O(3)-0.02BiAlO(3))]-xNaNbO(3) (BNT-BA-xNN) ceramics were investigated. It was found that hydrostatic pressure can induce a phase transformation from ferroelectric (FE) to relaxor (RE). Meanwhile, the FE-RE phase transition pressure (P-FR) tends to decrease as the NN addition increases. Moreover, increasing temperature exhibits a similar effect that is, reducing P-FR. The reduced P-FR were considered to result from the reduced FE stability and increasing proportion of RE phase. However, P-FR was obviously enhanced after poling, which can be attributed to the induced FE phase and the formation of macrodomains with application of an electric field. These results will aid in understanding the phase transition behavior of BNT-based relaxor ferroelectrics for applications under hydrostatic pressure.