Crystallographic characterization of epitaxial Pb(Zr,Ti)O3 films with different Zr/Ti ratio grown by radio-frequency-magnetron sputtering

Crystallographic structure of as-grown epitaxial Pb(Zr,Ti)O3 (PZT) films was investigated with regard to the Zr/Ti ratio and crystalline orientation. PZT films with (001) and (111) orientation were epitaxially grown on (100) and (111)SrTiO3 substrates respectively using radio-frequency (rf) sputtering. Four circle x-ray diffraction measurements revealed that the crystallographic dependence on Zr/Ti composition in PZT films was much different from bulk PZT. In particular, (001)-oriented PZT films showed tetragonal structure even in the Zr/Ti composition of 70/30 where the bulk PZT ceramics are rhombohedral phase. In addition, although (001)-oriented PZT films with Zr/Ti ratio of 53/47 and 70/30 showed tetragonal structure, (111)-oriented PZT films with the same Zr/Ti ratio were identified as the rhombohedral structure. The cell volume of the PZT films with both orientations increased, suggesting the excess Pb atoms in the films due to the impinging energetic sputtered particles induces the anomalous crysta...