The origin of the molecular field in ferromagnets Available to Purchase

Since students find it difficult to follow the discussions of ferromagnetism based on the exchange integral $(J)$ that appears in the Heitler–London treatment of the hydrogen molecule, partly because there it clearly favors antiparallel spins and partly because the curves showing its possible variation with the $d$-shell radius are clearly completely speculative, it is suggested that an approach based on the molecular orbital treatment, which explains the magnetic moment of the oxygen molecule, gives a more transparent basis for discussions of the origin of the molecular field in $3d$ metals.