Low-field magnetization features of superconducting tapes with strong pinning anisotropy

The electrodynamic behavior of II-type superconductors is determined by the physics of the vortex matter, for which the superconducting material is the medium of existence. It is noteworthy that for all practical superconductors this medium is both anisotropic and inhomogeneous. On the basis of data on the degree of inhomogeneity and anisotropy, some features of magnetization in low external field, comparable to self-field, can be explained. Namely: 1) an anomalous shift of the central magnetization peak, and 2) the fishtail shape in inclined magnetic fields. In this paper, we present an experimental study of the low-field magnetization of Nb-Ti tapes. The degree of anisotropy was varied by heat treatment of the original cold-rolled tape and by slicing the samples along and across the rolling direction. The obtained results are discussed in comparison with the features of the magnetization loops of other practical superconductors.