Revyakina M. Anisotropy of the critical current in single crystals YBa2Cu3O7-x, caused by the vortex lattice structure and twins

The dissertation is based on the results of investigation of the critical current anisotropy in the single crystals YBa2Cu3O7-x initiated by the twin boundaries and the layered structure. It is shown that the twins affected the configurational structure and pinning of the magnetic flux at the anglesc less than 8 degrees for the field orientation in the ab - plane and at the angles less than 70 degrees for the magnetic field rotating off the c - axis. In strong magnetic fields, the rotation of the field vector off the ab - plane leads to a transition from the elastic creep to the plastic creep, that is caused by the difference in the angular dependences of the activation energy between the elastic and plastic mechanisms of creep.