Elastic, Dielectric, Piezoelectric and Electromechanical Properties of Tetragonal Pb(Mg_1/3Nb_2/3)O_3-PbTiO_3 (PMN-PT)

Relaxor ferroelectric single crystal Pb(Mg1/3Nb2/3)O3-38%PbTiO3 (PMNT62/38) was grown directly from melt by a modified Bridgman technique. The XRD analysis confirms that PMNT62/38 single crystal has a tetragonal structure at room temperature. The er - T peak at Tc and little dispersion over measured temperature range indicate that the PMNT62/38 single crystal is a normal ferroelectric. The full set of electromechanical properties was determined by using an impedance resonance technique, the Curie temperature being about 174℃, piezoelectric constant d33-300pC/N, and permittivity e 33 -734 and e11 -4301. Electric-mechanical coupling coefficients measured are k33 84.6%, kt 60.8%, k31 44.5% and k15 45.9%.