Relaxor based fine grain piezoelectric materials

The dielectric and piezoelectric properties of polycrystalline ceramics of relaxor ferroelectric lead magnesium niobate-lead titanate modified with La/sub 2/O/sub 3/ (1-x) (Pb/sub 0.985/La/sub 0.01/) Square Operator /sub 0.005/(Mg/sub 1/3/Nb/sub 2/3/)O/sub 3/-(x)PbTiO/sub 3/, were investigated. The compositional range of 0.2 <or=x<or=0.4, being near the morphotropic phase boundary, was characterized. Lanthanum doping resulted in reduction of grain size, enhanced density, and a downward shift of the dielectric maximum temperature. The final microstructures of all compositions were fine with uniform grain size distributions. Room-temperature dielectric constants Ks of 5000 and piezoelectric constants d/sub 33(s)/ of 500 pC/N were found for compositions near the morphotropic phase boundary (x approximately=0.33).<<ETX>>