Influence of Zn and Ni substitutions for Mg on dielectric properties of (Mg4-xMx)(Nb2-ySby)O-9 (M = Zn and Ni) solid solutions

The effects of M substitution for Mg and Sb substitution for Nb in the (Mg4-xMx)(Nb2-ySby)O-9 (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 Mg-4(Nb2-ySby)O-9 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 Mg-4(Nb2-ySby)O-9 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 Mg-4(Nb2-ySby)O-9 solid solutions may related to the grain size decreased which is opposite to general results and this relation is consistent with that of Al2O3. (C) 2003 Elsevier Ltd. All rights reserved.