Abstract
The temperature variation of the saturation magnetization at low temperatures has been derived from the energy band, molecular field theory of ferromagnetism in metallic substances, and the results are expressed in terms of the structure of the density of states curve, the molecular field coefficient and the effective exchange constant for spin waves. A new term appears in the saturation magnetization which is proportional to T3/2 and which can become quite large as the relative alignment of the magnetic carriers becomes small. In the limit of very small relative magnetization, the curvature and slope of the density of states function is given in terms of experimentally determined quantities. The low temperature magnetization data for nickel have been analysed and a gap temperature for the single particle excitations of the order of several 100 °K has been deduced.
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