Effects of microstructure on microwave dielectric properties of Y2Ba(Cu1–xZnx)O5 solid solutions

The effect of the variations in the microstructure and lattice parameters on the microwave dielectric properties of Y2Ba(Cu1–xZnx)O5 solid solutions with and without MgO were evaluated in this study. The unit cell volumes with MgO are non-linearly changed with increasing the composition x, whereas those without MgO are parabolically increased. Thus, Mg2+ ions are substituted for Cu of Y2Ba(Cu1–xZnx)O5 solid solutions at x =0 and 0.25, and then Mg2+ substitution for Zn is induced over the composition x=0.5. In this case, the variations in the microstructure with substitution influence the Q·f values, and the highest value is 128333 GHz at x=0.25. The highest value of Q·f without MgO, is 113969 GHz at x=1. It is recognized that the grain growth induced by the difference of the sintering time exerts on Q·f values.