title: Imaging of a vortex lattice transition in YNi2B2C by scanning tunneling spectroscopy
abstract: The vortex lattices in YNi2B2C under the magnetic fields H up to 3 T applied along both the a and the c axes have been studied by scanning tunneling spectroscopy at 4.2 K. The vortex lattice transition has been found to occur in different manners for H parallela and H parallelc; in H parallela a slightly distorted hexagonal vortex lattice has been found to transform to a nearly square one above 1.0 T with increasing H, while in H parallelc the transition occurs at a much lower field around 0.1 T. The unconventional steep increase of the quasiparticle density of states outside the vortex core has also been found well below H(c2).
authors.affiliation: Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152, Japan.
authors.initials: H
authors.lastname: Sakata
authors.initials: M
authors.lastname: Oosawa
authors.initials: K
authors.lastname: Matsuba
authors.initials: N
authors.lastname: Nishida
authors.initials: H
authors.lastname: Takeya
authors.initials: K
authors.lastname: Hirata