Investigation of the new piezoelectric system (1-x)Bi(MgTi)0.5O3-xPbTiO3

An investigation was made into the (1−x)Bi(MgTi)0.5O3¿xPbTiO3 (BMT-PT) system. The aim was to find the optimum composition with respect to piezoelectric and dielectric properties and link this to the presence of a morphotropic phase boundary (MPB). The optimum composition was found to be 68 mol%BMT¿32 mol%PT with a broad active region of 36 mol%PT <x <40 mol%PT. The maximum values of the piezoelectric constants were d33 = 215 pm/V and d31 = 58 pm/V, respectively; the maximum relative dielectric constant 33/0 was 1046. The dielectric loss is high with over 5% up to almost 9%. It was also observed that the choice for the material of the electrode influences the properties considerably. The Vicker's hardness was 5.2 GPa while the strength as measured in 3-point bending was 230 MPa.