Role of Zn substitution for Cu on the microwave dielectric properties and crystal structure of Eu 2Ba(Cu 1− xZn x)O 5 solid solutions

Abstract

The synthesized Eu 2Ba(Cu 1− x Zn x )O 5 solid solutions were single phase over the whole composition range. The lattice parameters, a and b, increased, while the lattice parameter c decreased with increasing the composition x. The variations in the lattice parameters were found to be related to those of the MO 5 (M=Cu and Zn) pyramid caused by the difference in the ionic radii of Cu and Zn ions. The dielectric constant ( ε r) and the temperature coefficient of the resonant frequency ( τ f ) of Eu 2Ba(Cu 1− x Zn x )O 5 solid solutions were almost constant, ranging from 17.1 to 18.1 and from −25.4 to −29.5 ppm/°C, respectively, and the detrimental effect of Zn substitution for Cu on these properties was not apparent. The value of quality factor ( Q· f) in Eu 2Ba(Cu 1− x Zn x )O 5 solid solutions is 57921 GHz at x=0.75, and Zn substitution for Cu is effective in improving the Q· f values.