Influence of Zn and Ni substitutions for Mg on dielectric properties of (Mg4-xMx)(Nb2−ySby)O9 (M=Zn and Ni) solid solutions

The effects of M substitution for Mg and Sb substitution for Nb in the (Mg4−xMx)(Nb2−ySby)O9 (M=Zn and Ni) (x=0–2, y=0–1.5) solid solutions on the microwave dielectric properties were investigated in this study. The limits of both (Mg4−xMx)Nb2O9 (M=Zn and Ni) solid solutions were approximately x=2, whereas that of Mg4(Nb2−ySby)O9 solid solutions was approximately y=1.5. As for the Ni and Zn substitutions for Mg, the quality factor, Q·f values of the (Mg4−xMx)Nb2O9 (M=Zn and Ni) solid solutions decreased from 192 268 to 28 400GHz with increasing composition x from 0 to 2. On the other hand, the Q·f values of the Mg4(Nb2−ySby)O9 solid solutions were remarkably improved by the Sb substitution for Nb; the highest Q·f value of 285 423 GHz was obtained at y=1. It was found that an increase in the Q·f values of Mg4(Nb2−ySby)O9 solid solutions may related to the grain size decreased which is opposite to general results and this relation is consistent with that of Al2O3.