Persistent photoconductivity in YBa2Cu3Ox by visible and UV excitation below Tc

Abstract We studied the persistent photoconductivity in underdoped metallic YBa 2 Cu 3 O x ( x ≈6.6) by visible and UV excitation above and below T c . The results show that the photodoping effect exists also when the sample is in the superconducting state and that its efficiency is approximately the same as at low temperatures above T c . The dependence of the effect on the temperature where the photodoping is performed is essentially the same for visible light and UV radiation, i.e., a relatively small effect at low temperatures but a significantly larger effect near room temperature. We also observed that the efficiency is somewhat smaller with UV radiation, in contrast to previous results in semiconducting samples.