一次元反強磁性格子の帯磁率と比熱

Recent experimental studies concerning the specific heat, the susceptibility and the paramagnetic resonance of single crystals of CuSO_4・5H_2O and CuSeO_4・5H_2O in the temperature range below 1°K revealed that there are two kinds of copper ion present in a unit cell. It is supposed that each species of ions are arranged antiferromagnetically in a linear chain and there are weak interactions between them. For these substances a four sublattice model is presented, and applying the molecular field theory. The Neel point and the susceptibility versus temperature curves are explained. The speecific heat jump is also expected.