  Andreev reflection (AR) and Yanson point-contact spectroscopy (PCS) have been
applied simul-taneously to study the superconducting (SC) gap and the
electron-phonon interaction (EPI) in a Zn single crystal. The correlation
between SC gap value and EPI spectrum allowed us to establish the anisotropy of
the SC gap. Evidence for multiband superconductivity in Zn is present with two
gaps related as 1:1.3. We also found that the AR features are more robust
against the point-contact quality than the EPI ones, possibly, due to the large
coherence length in Zn compared to the typical PC size. Even for the PCs close
to the ballistic regime with intense EPI spectra, the transmission coefficient
evaluated from the AR spectra is near the one predicted theoretically for the
diffusive regime of a current flow in the PC. Understanding those phenomena
would provide a more reliable basis to apply both types of spectroscopies to
study more complex SCs.
