Effect of order–disordered nano-domains on the dielectric and electrical properties of PMNT ceramics

Abstract

0.9Pb 1− x La x (Mg 1/3Zn y Nb 2/3)O 3–0.1PbTiO 3 relaxor ferroelectric ceramics has been investigated to demonstrate the change of order–disordered nano-domains contributes to the dielectric and electrical properties of PMNT ceramics. Co-doping of the La 3+ and Zn 2+ was used to adjust the order–disordered nano-domain structure. After co-doping with the La 3+ and Zn 2+, the degree of order–disorder was remarkably increased. Moreover, an additional dielectric “shoulder” was observed in the temperature dependence of the dielectric constant. With increasing of the degree of order–disorder, the “shoulder” turned stronger and the dielectric peak turned fainter. For these compositions with different order–disordered nano-domains, the relative dielectric constant change with DC bias field was measured. When 2 mol% La 3+ and 3 mol% Zn 2+ were co-doped, the maximal relative dielectric constant change decreased from 70% to 23% at 1 kHz (1000 V/mm). The reduction of the polar nano-domains and the crystal anisotropy due to the improving of the degree of order–disorder was responsible for the remarkable increase of the electric field stability.