Spin-Wave Contribution to the Heat Capacity of Magnetite

The dispersion curve recently found by Milford and Glasser for the acoustical branch of the spin-wave spectrum of magnetite is used in a numerical calculation of the heat capacity. The results obtained are compared to the fit found by Kouvel for his low-temperature experimental data. It is found that the use of a more precise dispersion curve does not remove the disagreement between low-temperature heat-capacity determinations of the exchange constant and determinations based on measurement of the Curie temperature, but that it does destroy the apparent agreement between the low- and high-temperature measurements of the Debye temperature.