Coexistence of Superconductivity and Sinusoidal (Helical) Magnetic Order

The free energy of a superconductor in the presence of a sinusoidal (helical) magnetic order is considered. The method of projection is used to diagonalyze the electronic Hamiltonian. The wavelength 2π/Q of the sinusoidal (helical) phase of amplitude M is computed self‐consistently. A reduction of the cooper pair, M2/Q, is found which stabilizes the sinusoidal phase. Copyright © 1986 WILEY‐VCH Verlag GmbH & Co. KGaA