Pb(Mg1/3Nb2/3)O3 ceramics prepared via columbite method by using two types of Mg precursors, i.e. MgO and (MgCO3)4·Mg(OH)2·4H2O exhibit high crystallinity and high densification after sintering at 1200°C. 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)4·Mg(OH)2·4H2O. 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.
Properties of the Pb(Mg1/3Nb2/3)O3 Ceramics Prepared by Using Two Different Mg Precursors
CARNASCIALI, MARIA;
2008-01-01
Abstract
Pb(Mg1/3Nb2/3)O3 ceramics prepared via columbite method by using two types of Mg precursors, i.e. MgO and (MgCO3)4·Mg(OH)2·4H2O exhibit high crystallinity and high densification after sintering at 1200°C. 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)4·Mg(OH)2·4H2O. 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.
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