Local grain orientation and strain in polycrystalline YBa2Cu3O7-δ superconductor thin films measured by Raman spectroscopy

We report direct measurements of local grain orientation and residual strain in polycrystalline, C-axis oriented thin YBa2Cu3O7-delta superconducting films using polarized Raman spectroscopy. Strain dependence of the A(g) Raman active mode at 335 cm(-1) was calibrated and used to measure local strain in the films. Our data showed that high quality films are associated with the connected path of uniform grain orientation (single crystal-like) across the film and uniform residual strain in the range of -0.3%. Nonuniform grain orientation or high angle grain boundaries and nonuniform local strains were associated with low quality films. (C) 2001 American Institute of Physics.