Néel Temperature of the Spin Density Wave

抄録

The Néel temperature, T_N, of the spin density wave in a b. c. c. lattice, proposed by Tachiki and Nagamiya, is calculated. It is found that the transition of the second kind can be predicted only for k_FO (the Fermi radius at absolute zero)≥π⁄a (a: the lattice constant), where one has antiferromagnetic ordering immediately below T_N. For k_FO<π⁄a, a transition of the first kind at a certain temperature above T_N can be inferred, if one understands by T_N the temperature at which the amplitude of the spin density wave tends to zero.