  We present results of in field directional point contact spectroscopy (DPCS)
study in the quaternary borocarbide superconductor YNi2B2C, which is
characterized by a highly anisotropic superconducting gap function. For I||a,
the superconducting energy gap (D), decreases linearly with magnetic field and
vanishes around 3.25T which is well below the upper critical field (Hc2~6T)
measured at the same temperature (2.2K). For I||c, on the other hand, D
decreases weakly with magnetic field but the broadening parameter (G) increases
rapidly with magnetic field with the absence of any resolvable feature above
3.5T. From an analysis of the field variation of energy gaps and the zero bias
density of states we show that the unconventional gap function observed in this
material could originate from multiband superconductivity.
