The interaction of two radio waves with noticeably different frequencies omega and omega ₁ ( omega >> omega ₁) inside a tungsten single-crystal plate at liquid-helium temperature have been studied. The magnetodynamic mechanism of non-linearity owing to the existence of the high-frequency wave with a large amplitude H has been realized. The low-frequency surface impedance Z was analysed as a function of H and DC magnetic field H. The hysteresis of Z(H) was found and studied. The origin of this non-linear phenomenon which has a threshold character is connected with the generation of the current states.