Spin Density Wave in Magnetic Field

Abstract

The effect of magnetic field on the spin density wave based on the one-band model is studied with respect to two points, one the instability of the ferromagnetic state at high fields by a perturbing infinitesimal spin density wave and the other the susceptibility of a helical spin density wave for a field perpendicular to the plane of the spin rotation. The instability occurs by a helical or sinusoidal spin density wave whose oscillation is perpendicular to the magnetization. The corresponding critical field is calculated as a function of the intra-atomic Coulomb integral U for various values of the Fermi radius k _F . The perpendicular susceptibility is also calculated for the same parameter values.