Transport Property Improvement by Means of BZO Inclusions in PLD GrownYBCO Thin Films

Abstract

A detailed study on YBa2Cu3O7-delta (YBCO) films with BaZrO3 (BZO)inclusions (YBCO-BZO) deposited on SrTiO3 substrate with different BZOcontents is presented. X ray diffraction, SEM imaging andsuperconductive critical temperature (T-c) measurements were performedto evaluate film growth quality. Independently from the BZO content,all YBCO-BZO films showed T-c values close to that of pure YBCOindicating that the T-c reduction which is usually observed on YBCO-BZOfilms can be successfully recovered by changing the depositionconditions. All YBCO-BZO films showed an improved critical currentdensity (J(c)) dependence on magnetic field if compared to the typicalJ(c)(H) of YBCO, resulting in higher irreversibility fields up to 9 Tat 77 K. SEM observation on etched samples suggests a direct linkbetween the defect density measured in YBCO-BZO samples and thatcalculated from the observed in field performances. The analysis ofJ(c)(B) as a function of applied magnetic field direction revealed thatthe pinning due to isotropic pinning centers typical for YBCO iscoupled with a c-axis correlated pinning in YBCO-BZO which can beascribed to BZO induced columnar defects. J(c)(B) recorded at severaltemperatures down to 10 K revealed matching effect features.