A comparison of calculated and measured critical temperatures in Heisenberg magnetic materials

Critical temperatures are calculated for the ferromagnets EuO and EuS and for the antiferromagnets, RbMnF3, MnF2, NiF2, KMnF3, NiO and MnO using high-temperature series techniques and exchange constants as derived from the measurements of spin-wave dispersion relations. After correcting for thermal expansion and other small effects the predicted transition temperature should be good to between 0.6% in the most favourable case and 6% in the …