The lead magnesium niobate-lead titanate (PMN-PT) crystal is a new generation of piezoelectric materials. The chemical structural formula of PMN-PT is (1-x)[Pb(Mg1/3Nb2/3)O3]-x[PbTiO3].The PMN-PT is formulated to exhibit high piezoelectric coefficient, large electric-mechanical coupling coefficient, high dielectric constants and low dielectric losses. As a rule, the piezoelectric coefficient is higher than PZT ceramics, which results in improving bandwidth, sensitivity and source level in applications.