  Evolution of the vortex lattice, the rhombus-square transition included, for
LuNi_2B_2C in the field along the c crystal axis, is tracked by the decoration
technique pushed up to the record high (for this method) field of 1480 Oe.
Decoration images are analyzed with the help of the Fourier transform, which
indicates disordered structures in small fields of a few Oe. In fields H < 200
Oe the coexisting domains of different structures are observed. A technique
based on the Fourier transform is employed to see the domains separately. The
transition to the square lattice is recorded near 900 Oe. The results are in
agreement with predictions of the nonlocal London theory.
