Dependence of the amplitude of magnetoquantum oscillations of the metallic point-contact resistance on the bias voltage

Magnetoquantum oscillations of resistance as functions of the potential difference applied across the contact are studied for metallic point contacts made of $Al$ and $Be$. The amplitude of resistance oscillations in a magnetic field increases with voltage and is identical to the EPI spectrum of the point contact for one group of contacts, and with the bias voltage across the contact for another. The increase in the oscillation amplitude as well as its decrease has a nonmonotonic dependence on energy. The scattering of electrons by nonequilibrium phonons and the Fermi-liquid effects in the nonequilibrium electron system are considered as the possible reasons behind the observed effects.