Critical current density and flux pinning in Y1-xHoxBa2Cu3O7-delta epitaxial films

The critical current density J(c) of Y1-xHoxBa2Cu3O7-delta (YHBCO) epitaxial thin films with x=0, 0.2, 0.4, 0.7 at various temperatures and magnetic fields has been measured magnetically. The J(c) and flux pinning density Fp values are significantly enhanced with the Ho substitute amount x with the optimal effect achieved at Ho concentration around x = 0.4 in the entire measured temperature (30-77 K) and magnetic field (0-3 T) ranges. X-ray diffraction patterns have shown that the greater the lattice deformation, the higher the J(c) of the films.