Effect of heterogeneous interface on the microwave dielectric properties of Ca(Mg1/3Nb2/3)O3/CaTiO3 thin films

Abstract Effects of heterogeneous interface on the dielectric properties of Ca(Mg1/3Nb2/3)O3/CaTiO3 (CMN/CT) thin films fabricated by Pechini technique were investigated in this work. As-prepared CMN/CT thin films were uniform, smooth and dense with the thickness of around 190 nm. AFM results showed that the root mean square (RMS) surface roughness of CMN/CT thin films decreased as the heterogeneous interface numbers increases and the NI-11 sample possesses minimal RMS. Compared with measured results, the calculated dielectric constant was slightly lower and with increasing heterogeneous interface numbers, the measured dielectric constant of the films increased gradually while the dielectric loss decreased. These results implied that heterogeneous interfaces were favorable for the improvement of dielectric properties, which was also attributed to the formation and accumulation of depletion layers at the CMN/CT interfaces that reduced lattice relaxation. Being indexed by XRD patterns and EDS spectrum, the inter-diffusion between the CMN and CT layer was further confirmed. Moreover, the CMN/CT thin films had single phase in their own layers independently regardless of interface number.