Eskildsen, M. R.Gammel, P. L.Barber, B. P.Ramirez, A. P.Bishop, D. J.Andersen, N. H.Mortensen, KellBolle, C. A.Lieber, C. M.Canfield, P. C.2019-09-271997Eskildsen, M. R., P. L. Gammel, B. P. Barber, A. P. Ramirez, D. J. Bishop, N. H. Andersen, K. Mortensen, C. A. Bolle, C. M. Lieber, and P. C. Canfield. 1997. “Structural Stability of the Square Flux Line Lattice in YNi 2 B 2 C and LuNi 2 B 2 C Studied with Small Angle Neutron Scattering.” Physical Review Letters 79 (3): 487–90. https://doi.org/10.1103/physrevlett.79.487.0031-90071079-71141092-0145http://nrs.harvard.edu/urn-3:HUL.InstRepos:41417272We have studied the flux line lattice in YNi2B2C and LuNi2B2C, the nonmagnetic end members of the borocarbide superconductors using small angle neutron scattering and transport. For fields, H parallel to c, we find a square symmetric lattice which disorders rapidly above H/H-c2 similar to 0.2, well below the ''peak effect'' at H/H-c2 = 0.9. The results 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.en-USJournal Article2019-09-2710.1103/PhysRevLett.79.487