Microstructure and Microwave Dielectric Properties of xCa(Al0.5Nb0.5)O3+(1−x)SrTiO3 Solid Solutions

The crystal structure evolution and microwave (MW) dielectric properties of xCa(Al0.5Nb0.5)O3+(1−x)SrTiO3 (xCAN+(1−x)ST, 0≤x≤1.0, ) dielectric ceramics were investigated. X-ray diffraction patterns illustrated that a single perovskite solid solution could be formed between the two end members; however, minor amount of pyrochlore phase was also detected in the composition range of 0.5≤x≤0.9. With the increase of x value, the crystal structure gradually evolved from a simple Pm3m cubic to a monoclinic P21/n space group with the octahedral tilting and the B-site ordering structure transition subsequently developed. The MW dielectric properties of xCAN+(1−x)ST solid solutions were elaborately investigated and correlated to their crystal structures. The microscopic structure-related thermal parameters in the xCAN+(1−x)ST solid solution were analyzed in terms of the Claussius–Mossotti equation to reveal the original contributors in temperature coefficients. Temperature coefficient-compensated ceramic could be obtained in the xCAN+(1−x)ST system in the range of 0.5