[en] For a single crystal of YNi(2)B(2)C superconductor, the equilibrium magnetization M in the square basal Plane has been studied experimentally as a function of temperature and magnetic field. While the magnetization M(H) deviates from conventional London predictions, a recent extension of London theory (to include effects of nonlocal electrodynamics) describes the experiments accurately. The resulting superconductive parameters are well behaved. These results are compared with corresponding findings for the case with M perpendicular to the basal plane.
