The correlations between electronic polarizability, packing fraction, bond energy and microwave dielectric properties of Nd(Nb1−xSbx)O4 ceramics

In this paper, Nd(Nb1−xSbx)O4 ceramics were prepared via a solid-state reaction method. The X-ray diffraction patterns of Nd(Nb1−xSbx)O4 ceramics showed the monoclinic fergusonite structure of NdNbO4 and a second phase Nd4Sb6O21 were obtained. For the first time, the correlations between electronic polarizability, packing fraction, bond energy and microwave dielectric properties of Nd(Nb1−xSbx)O4 ceramics were discussed. For the main phase NdNbO4, εr was strongly dependent on the electronic polarizability. With the increase of packing fraction, Q × f values were increased. The decrease of τƒ values were mainly attributed to the decreasing of the B-site bond energy. With the increase of the x values, the B-site bond energy became weak, and the Nd(Nb1−xSbx)O4 system tend to instable. An optimal microwave dielectric properties with high Q × f = 73,200 GHz was obtained for Nd(Nb1−xSbx)O4 (x = 0.08) ceramics sintered at 1250 °C for 4 h.