Effects of La substitution for Nd in (Nd 2− xLa x)BaZnO 5 solid solutions on microwave dielectric properties and crystal structure

Abstract

The synthesis and microwave dielectric characterization of (Nd 2− x La x )BaZnO 5 solid solutions were studied. The samples obtained were single phase over the whole composition range and the lattice parameters of solid solutions were linearly increased with increasing the composition. Moreover, the expansion of the volume in the RO 8 ( R=Nd and La) and BaO 10 polyhedra and ZnO 4 tetrahedron were recognized when Nd ions were substituted by La. These variations in the lattice parameters and volumes of the polyhedra are basically attributed to the differences in ionic radii between Nd 3+ and La 3+ ions. From the evaluation of microwave dielectric properties, it was shown that the appropriate τ f values ranging from 4.6 to −5.0 ppm/°C are obtained by La substitution for Nd ion, and the highest Q · f value was 17,832 GHz at x=2.