Apparent anisotropy effects of upper critical field in high- textured superconducting Nb-Ti tapes

Analysis of the voltage-field characteristics of superconducting niobium-titanium tapes is the objective of this work. We used both the original cold-rolled and heat-treated tapes, whose structure and texture we had studied in detail. We observed anisotropy in the upper critical field and the reduction of the transition width with increasing angle between the plane of tape and the direction of the magnetic field. In addition, we have registered a significant difference of the upper critical field values, obtained from the voltage-field characteristics and field dependence of the pinning force. Considering our results, we suggest an explanation of the observed features within the macro-inhomogeneity model.