  A Weyl semimetal is a topologically non-trivial phase of matter that hosts
mass-less Weyl fermions, the particles that remained elusive for more than 80
years since their theoretical discovery. The Weyl semimetals exhibit unique
transport and magneto-transport properties and remarkably high surface spin
polarization. Here we show that a unique mesoscopic superconducting phase with
a critical temperature up to 7 K can be realized by forming metallic point
contacts with silver (Ag) on single crystals of TaAs, while neither Ag nor TaAs
are superconductors. The Andreev reflection spectra obtained from such point
contacts are fitted well within a modified Blonder-Tinkham-Klapwijk (BTK) model
with a superconducting energy gap up to 1.2 meV. The analysis within this model
also reveals high transport spin polarization up to 60\% indicating a spin
polarized supercurrent flowing through the point contacts on TaAs. Such point
contacts also show a large anisotropic magnetoresistance (AMR) originating from
the spin polarized current. Therefore, apart from the discovery of a novel
mesoscopic superconducting phase and it's coexistence with a large spin
polarization, our results also show that the point contacts on Weyl semimetals
are potentially important for applications in spintronics.
