Current induced optical birefringence in superconducting YBaCuO (123) and BiSrCaCuO (2212) thin films

Abstract We have observed that the flow of an electric current through superconducting YBCO and BiSrCaCuO thin films induces an increase in the optical birefringence, characteristic of a chance in the crystal symmetry. This symmetry breaking is confirmed by Raman spectroscopy and is tentatively explained by ionic displacement within the CuO2 planes and lattice distorsion.