S. Behler et al., VORTEX PINNING IN ION-IRRADIATED NBSE2 STUDIED BY SCANNING-TUNNELING-MICROSCOPY, Physical review letters, 72(11), 1994, pp. 1750-1753
Vortex pinning by columnar defects in a NbSe2 crystal irradiated with
2.2 GeV Au+14 ions is studied by scanning tunneling microscopy (STM) a
t 3 K. The vortex arrangement is clearly resolved in magnetic fields u
p to 500 mT and compared to the defect locations, also extracted from
STM data. At vortex densities much larger than the defect density, the
triangular vortex lattice is perturbed close to the defects. At vorte
x densities comparable or smaller, only some defects trap a vortex and
the whole vortex arrangement is disordered, although less random than
the defect distribution.