  The magnetic field dependence of low temperature specific heat in YNi2B2C was
measured and analyzed using various pairing order parameters. At zero magnetic
field, the two-gap model which has been successfully applied to MgB2 and the
point-node model, appear to describe the superconducting gap function of
YNi2B2C better than other models based on the isotropic s-wave, the d-wave line
nodes, or the s+g wave. The two energy gaps, delta_L=2.67 meV and delta_S=1.19
meV are obtained. The observed nonlinear field dependence of electronic
specific heat coefficient, gamma(H)~H0.47, is quantitatively close to
gamma(H)~H0.5 expected for nodal superconductivity or can be qualitatively
explained using two-gap scenario. Furthermore, the positive curvature in Hc2(T)
near Tc is qualitatively similar to that in the other two-gap superconductor
MgB2.
