The effect of residual stresses and dislocations on microwave dielectric loss in rutile-related (Ti0.6Zr0.4)0.8(Zn1/3Nb2/3) sub 0.2O

Strain and stress play an important role in functional materials, but they are often neglected in electroceramics. Here we report the stress effect on microwave dielectric loss in rutile-related (Ti0.6Zr0.4)0.8(Zn1/3Nb2/3)0.2O2 solid solutions. The macroscopic, microscopic and nano-scale residual stresses have been systematically investigated, including their relationships. The average Raman spectra have demonstrated considerable macro-residual stresses, especially for the heavily cracked sample. The high-resolution Raman images reveal the inhomogeneity of residual stress distribution at the grain-level, which is reflected by the shifts of Raman-active modes. The high-resolution transmission electron microscope (HRTEM) images and geometric phase analysis (GPA) analysis show the aggregation of dislocations and resulting distortion of crystal. It can be found that the dielectric loss depends strongly on residual stresses, that samples with greater residual stress exhibit much higher dielectric loss because the residual stress increases the vibration anharmonicity of the lattice.