Raman scattering from sputtered films of YBa2Cu3Oy

Abstract

Thin films of the high-temperature superconductor YBa2Cu3Oy have been deposited on Al2O3 and MgO substrates by dc magnetron sputtering. Raman-scattering experiments have been carried out on these films at various temperatures. The results of these experiments have been used to estimate the amount of impurity phases in the films, to characterize the actual superconducting films, and to test for any preferential orientation within the film. Vibrational modes of the superconductor were found at 148, 226, and 338 cm−1 in both sets of films, at 446 and 491 cm−1 in the Al2O3 films, and at 441 and 500 cm−1 in the MgO films. The measured frequencies of the highest energy modes have been used to determine the oxygen content of the films.