Relationship between distortion of crystal structure and dielectric properties of complex perovskite oxide Ba(Co,Zn)1/3Nb2/3O3 thin films

The oxygen octahedral can be distorted by epitaxial strain due to the lattice mismatch. The epitaxial strain (epsilon(yy)) linearly decreases from - 0.244% to - 0.445% with the growth temperature. Thin films grow along c axis on the SrTiO3 substrate and exhibit the epitaxial relationship of Ba(Co,Zn)(1/3)Nb2/3O3 (001) // SrTiO3 (001). The superlattice reflections arising from in-phase tilting of the oxygen octahedra are clearly visible along [010] and [111] zone axis. The IR modes at 330 cm(-1) and 390 cm(-1) related to in-phase tilting are observed in far-infrared reflectivity spectroscopy. The calculated Qxf values from far-infrared reflectivity spectra of films grown at 550 degrees C to 700 degrees C increases from 51,000 GHz to 91,000 GHz mainly due to the enhancement of crystalline quality. The intrinsic quality factor (Q) is mainly contributed by O-(Co, Nb)-O and O-(Zn, Nb)-O bonding modes, while in-phase tilting in BCZN films may result in enhanced dielectric constants.

Automated summary

The oxygen octahedral can be distorted by epitaxial strain caused by lattice mismatch. Epitaxial strain decreases linearly with the growth temperature. Infrared reflectivity spectroscopy shows infrared modes related to in-phase tilting. The intrinsic quality factor of the thin films increases with the improvement of crystalline quality.