Magnetic properties of 3d transition-metal dichalcogenides with the pyrite structure

Magnetic properties observed experimentally in the 3d transition-metal dichalcogenides with the pyrite structure are reviewed and compared with properties expected theoretically for the Hubbard model. As characteristics of electrons in a narrow band, the following are discussed: (1) The temperature induced and field induced local moment in Co(S,Se)2 and (Co,Ni)S2. (2) The metal-nonmetal transition in NiS2 and its solid solutions. (3) The paramagnetism and antiferromagnetism in the exchange-enhanced metal Ni(S,Se)2.