LOWER CRITICAL FIELDS OF TEXTURED HIGH-T-C SUPERCONDUCTORS

The possibility of studying the anisotropy of lower critical fields in HTS materials during the measurements of critical currents of texture d samples subjected to the action of magnetic fields applied in three different directions is explored in the theory of magnetic properties of anisotropic superconductors. The critical fields H-c1(ab) and H-c1( c) of the high-T-c materials YBa2Cu3O7-delta and DYBa2Cu3O7-delta are determined at T = 77.3 K. It is found that the dependences H-c1(ab)(m( c)/m(ab)) and H-c1(c)(m(c)/m(ab)) are universal for all the investigat ed samples. (C) 1997 American Institute of Physics.