  Point-contact (PC) investigations on the title compound in the normal and
superconducting (SC) state (Tc=10,6 K) are presented. The temperature
dependence of the SC gap of TmNi2B2C determined from Andreev-reflection (AR)
spectra using the standard single-gap approximation (SGA) deviates from the BCS
behavior in displaying a maximum at about Tc/2. A refined analysis within the
two-gap approximation provides evidence for the presence of a second gap twice
as large as the main gap (the first one), while the latter is close to that
within the SGA. This way, TmNi2B2C expands the number of nickel borocarbide
superconductors which exhibit a clear multiband character. Additionally, for
the first time "reentrant" features were found in the AR spectra for some PCs
measured in a magnetic field. The PC spectroscopy of the electron-boson
interaction in TmNi2B2C in the normal state reveals a pronounced phonon maximum
at 9.5meV and a more smeared one around 15 meV, while at higher energies the PC
spectra are almost featureless. Additionally, the most intense peak slightly
above 3meV observed in the PC spectra of TmNi2B2C is presumably caused by
crystalline-electric-field (CEF) excitations. The peak near 1meV detected for
some PC spectra is connected with a modification of the CEF probably due to
boron or carbon vacancies, allowing to probe the local stoichiometry by PC
spectroscopy.
