Pinning of vortices by parallel twin boundaries in superconducting single crystals

Abstract

Pinning of a vortex array by parallel twin boundaries is theoretically investigated. The phase diagram, the magnetic torque, and the resistance in the external magnetic field rotated in the a-b plane are studied. In a dense vortex array the collective effects due to long-range interaction between vortices become of importance. They confine the distortion of the vortex array near the twin boundaries to distances of order of the intervortex spacing, thereby suppressing the influence of the twin boundaries on the whole vortex-array pattern when the magnetic field is increased. Nevertheless, the critical angle between the magnetic field and the twin boundaries, at which pinning onset takes place, weakly depends on the magnetic-field value, in agreement with experiment. It is shown that measurement of the Hall resistance is an effective tool to study pinning by twin boundaries.