TRANSPORT-PROPERTIES AND SUPERCONDUCTING FLUCTUATIONS IN OXYGEN-DEFICIENT YBA2CU3O7-DELTA THIN-FILMS

Measurements of the electrical resistivity, the Hall effect, and the magnetoresistance in oxygen-deficient thin films of YBa2Cu3O7-delta on LaAlO3 substrates in a temperature range from T-c approximate to 53 K up to 400 K are presented. A distinct kink in the resistivity curve and a sign change of the slope of the Hall-coefficient's temperature dependence were found around 320 K and are attributed to a structural phase transition, presumably a reordering of oxygen atoms. An investigation of the magnetoresistance due to superconducting fluctuations revealed the in-plane and out-of-plane coherence lengths xi(ab)(0) = 2.65 nm, xi(c)(0) = 0.09 nm, respectively, indicating the higher anisotropy in the oxygen deficient YBa2Cu3O7-delta compounds.