Visualization of vortex pinning in NbSe2 by scanning tunneling microscopy

Abstract We study vortex pinning in 2.2 GeV Au-ion irradiated NbSe 2 by scanning tunneling microscopy at 3 K. The irradiation generates columnar defects which act as pinning sites. The vortex arrangement is clearly resolved over a wide range of magnetic fields but shows strong distortions which correlate with the location of individual defects.