On the possible coexistence of itinerant-electron antiferromagnetism with the itinerant-electron ferromagnetism

It is shown that in an electron gas with coexisting charge density wave and spin density wave a spontaneous magnetization can occur. In the first paramagnetic region (T,T_t;Δ_s = Δ_t = 0) the spin susceptibility is independent of temperature (Pauli paramagnetism). In the second paramagnetic region (T_K<T<T_t,Δ_t≠0;Δ_s=0) the total susceptibility of the spin density wave is enhanced by a temperature dependent paramagnetic susceptibility with a Curie type law. This reflects the instability of the system to the formation of a charge density wave or to ferromagnetism. At sufficiently low temperatures (T～T_K) the spin susceptibility is anomalous great a fact which cannot be explained with the standard Fedders-Martin theory. Experimental results for pure chromium are in good agreement with our predictions.