Magnetic and Flux Pinning in Hg-Based HTS Thin Films

摘要

We have studied the critical current density (J(sub c)) as functions of temperature and magnetic field in epitaxial c-axis oriented Hg-1212 and Hg-1223 thin films. J(sub c) near 2 MA/sq cm at 100K and zero field can be achieved when the weak links between the grains are minimized through epitaxial growth of the film. This results in high irreversibility lines in these films. With the addition of columnar defects, the irreversibility line can be further increased within a certain field range. Moreover, an interesting scaling change with increasing pinning is attributed to an improved pancake vortex coupling along the c-axis of the film.