  We present a proposal to search for QCD axions with mass in the 200 $\mu$eV
range, assuming that they make a dominant component of dark matter. Due to the
axion-electron spin coupling, their effect is equivalent to the application of
an oscillating rf field with frequency and amplitude fixed by the axion mass
and coupling respectively. This equivalent magnetic field would produce spin
flips in a magnetic sample placed inside a static magnetic field, which
determines the resonant interaction at the Larmor frequency. Spin flips would
subsequently emit radio frequency photons that can be detected by a suitable
quantum counter in an ultra-cryogenic environment. This new detection technique
is crucial to keep under control the thermal photon background which would
otherwise produce a too large noise.
