Mr. Eskildsen et al., STRUCTURAL STABILITY OF THE SQUARE FLUX-LINE-LATTICE IN YNI2B2C AND LUNI2B2C STUDIED WITH SMALL-ANGLE NEUTRON-SCATTERING, Physical review letters, 79(3), 1997, pp. 487-490
We have studied the flux line lattice in YNi2B2C and LuNi2B2C, the non
magnetic end members of the borocarbide superconductors using small an
gle neutron scattering and transport. For fields, H parallel to c, we
find a square symmetric lattice which disorders rapidly above H/H-c2 s
imilar to 0.2, well below the ''peak effect'' at H/H-c2 = 0.9. The res
ults for H/H-c2 < 0.2 can be understood within the collective pinning
model, and are controlled by the tilt modulus c(44). For H/H-c2 > 0.2,
the disordering appears to be associated with the field dependence of
the shear modulus, C-66.