Direct observation of the magnetic flux tuning to the pinning structure in NbTi

The tuning of the magnetic fluxes to the pinning structure oriented along superconducting filaments is the reason of the existence of the magnetic field component B/spl perp/ perpendicular to the external magnetic field H. The dependence B/spl perp/ from the value and the orientation of an external magnetic field H is measured for multifilamentary NbTi sample. The flux capture by the pinning structure is observed when an external magnetic field is almost parallel to filaments. The dependence B/spl perp/ from the external magnetic field value allows estimating the pinning structure scale of the superconductor.