Burns, Ńel, and structural phase transitions in multiferoic Pb (Fe23 W13) O3 -xPbTi O3 detected by an acoustic emission

We investigated the ceramics samples of multiferoic solid solution of relaxor ferroelectric Pb (Fe23 W13) O3 with ferroelectric PbTi O3 (abbreviated as PFW-xPT; x=0, 0.25, and 0.37) by means of acoustic emission (AE) method and simultaneously using the dielectric measurement below 700 K. A distinct AE response has been detected at Burns temperature Td ≈640-650 K, where the dynamic polar clusters start to appear, at intermediate temperature of 510-520 K, where the polar clusters become probably static, at ferroelectric phase transition temperatures Tc, and at Ńel antiferromagnetic phase transitions. The Ńel temperatures TN in ceramics were observed to be lower than in the crystals; the origin is discussed. Based on detected AE responses, we have corrected previously obtained phase diagram for PFW-xPT system.