The vortex lattices in LuNi2B2C single crystals

Vortex lattices in LuNi2B2 C have been investigated by the decoration metho d at fields 20-1000 Oe at liquid helium temperatures and in a field cooling regime. At small fields of 20-200 Oe we have observed vortex lattice domai ns with different lattices orientations. Domains size increased with magnet ic field increase. At low fields vortex lattices closepacked directions in small domains do not correlate with crystal directions and the correlations become stronger at greater fields. One of the closepacked vortex arrays di rections within a domain becomes parallel to [110] or [100] directions. The vortex lattices themselves evolve at larger fields. The vortex lattice is aligned with the [100] direction and its rhombic cell apex angle beta incre ases from 64 degrees at 180 Oe to 75-90 degrees at 1000 Oe. (C) 2000 Elsevi er Science B.V. All rights reserved.