MODERN PHYSICS LETTERS B, cilt.20, sa.29, ss.1847-1852, 2006 (SCI-Expanded)
The resistive properties and activation energy of YBa2Cu3O7-delta (YBCO) superconducting materials change in magnetic field. It is explained that magnetoresistive behavior in terms of the presence of two-dimensional vortices being pinned effectively when they are perpendicular to the CuO2 planes and an exponential behavior of the activation energy versus the applied field was obtained. The resulting activation energies ranging from 1 to 5 Tesla were attributed to inter-granular flux creep process.