Burns, Neel, and structural phase transitions in multiferoic Pb(Fe2/3W1/3)O3-xPbTiO3 detected by an acoustic emission

We investigated the ceramics samples of multiferoic solid solution of relaxor ferroelectric Pb(Fe2/3W1/3)O-3 with ferroelectric PbTiO3 (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 T-d approximate to 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 T-c, and at Neel antiferromagnetic phase transitions. The Neel temperatures T-N 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. (c) 2008 American Institute of Physics.