Investigation of the amorphous to crystalline phase transition of chemical solution deposited Pb(Zr_0.3Ti_0.7)O₃ thin films by soft X-ray absorption and soft X-ray emission spectroscopy

Chemical solution deposited (CSD) complex oxide thin films attract considerable interest in various emerging fields as for example, fuel cells, ferroelectric random access memories or coated conductors. In the present paper the results of soft-X-ray spectroscopy between 280 and 560 eV on the amorphous to crystalline phase transition of ferroelectric Pb(Zr_0.3Ti_0.7)O₃ (PZT) thin films are presented. Five CSD samples derived from the same wafer coated with a PZT film pyrolyzed at 350 °C were heat treated at different temperatures between 400 and 700 °C. At first the samples were morphologically and electrically characterized. Subsequently the soft-X-ray absorption and emission experiments were performed at the undulator beamline 8.0 of the Advanced Light Source of the Lawrence Berkeley National Laboratory. Soft-X-ray absorption spectra were acquired for the Ti L _2,3-, O K-, and C K-edge thresholds by using simultaneously the total electron yield (TEY) and total fluorescence yield (TFY) detection methods. For two samples, annealed at 400 and 700 °C, respectively, the resonant inelastic soft-X-ray spectroscopy (RIXS) was applied for various excitation energies near the Ti L-, O K-edges. We observed clear evidence of a rutile phase at untypically low temperatures. This rutile phase transforms into the perovskite phase upon increasing annealing temperature. These results are discussed in the framework of current microscopic models of the PZT (111) texture selection.