Stability Theory of the Magnetic Phases for a Simple Model of the Transition Metals

A semiquantitative explanation of the observed distribution of magnetism in the transition metals and alloys is made based on a highly simplified quasiparticle band model. It depends on only two parameters, the valence (number of d electrons) of the metal and the ratio of quasiparticle interaction strength to band-width, C₀ / E^′′. The quantity C₀ / E^′′ increases with valence and also increases as one goes from the 5d transition metals to the 3d transition metals. Ferromagnetism is found to be most likely for those metals with large C₀ / E^′′ and a valence well away from five. Antiferromagnetism is found to occur for a valence of around five, as do the more complex states such as the ferrimagnetic and spiral-spin-density-wave states, which are explicitly described. It is suggested that the peak in the specific heat of the transition-metal alloys that occurs as one alloys across the 3d transition series is closely related to changes in the band structure caused by ordering, at least for the Cr-Mn system.