Dielectric Properties of Strontium-sugstituted Lead Magnesium Tungstate up to Microwave Frequencies

Pb 1-x Sr x (Mg 1/2 W 1/2 )O₃ ceramics for application in the microwave frequency range were investigated by dielectric constant and X-ray diffraction measurements. The dielectric constant curves showed two concentration dependent characteristics in the Pb(Mg 1/2 W 1/2 )O₃-rich region. As the Sr constant further increases to x=0.3 the dielectric curve levels off. In the concentration range between x=0.4 and x=1 in which dielectric constant dependence on temperature is negligible, it decreases and Qf value increases in the microwave frequency with increasing Sr. The temperature coefficient (τ e ) of the dielectric constant changes from the negative to positive value between x=0.9 and x=1. The dielectric constant, Qf and τ e are correlated with tolerance factor (t). From the X-ray diffraction results for 0.1≤x≤1 the cell parameter is found to decrease as x increases and B-site ordering is observed in all the composition ranges.