Magnetic properties of new Haldane gap materials

Abstract High-field magnetization and susceptibility measurements have been performed on the linear-chain Heisenberg antiferromagnets Ni(dmpn) 2 N 3 (CIO 4 ) and catena-(μ-N 3 )⦜Ni(323-tet)](CIO 4 ). These compounds have an energy gap at low temperatures, and the values of energy gap, crystalline field constants are estimated from the high-field magnetization data.