Properties of the Pb(Mg1/3Nb2/3)O3 Ceramics Prepared by Using Two Different Mg Precursors

Pb(Mg1/3Nb2/3)O3 ceramics prepared via columbite method by using two types of Mg precursors, i.e. MgO and (MgCO3)4Mg(OH)24H2O exhibit high crystallinity and high densification after sintering at 1200C. Higher amounts of pyrochlore phases were detected in the PMN sample obtained by using (MgCO3)4 Mg(OH)2.4H2O as precursor. This compositional difference, determines, for all frequencies, a shift of 50 K of the temperature corresponding to the permittivity maximum Tm for the sample derived from (MgCO3)4Mg(OH)24H2O. From this reason, better dielectric properties were obtained at room temperature for this PMN sample, although a higher dielectric permittivity at Tm was obtained for the sample derived from MgO precursor.