Field-induced high coercive ferromagnetic state and magnetoresistance in the antiferromagnetically ordered compound Fe0.5TiS2

The measurements of the magnetic susceptibility, magnetization, electrical resistivity and magnetoresistance have been performed for the Fe intercalated compound Fe0.5TiS2. According to X-ray diffraction measurements the Fe0.5TiS2 compound synthesized in the present work has a monoclinic crystal structure (space group I12/m1) which results from the ordering of Fe ions and vacancies between S-Ti-S tri-layres. The changes in the heat-treatment conditions at temperatures below 1100 Celsius degrees do not lead to an order-disorder transition within the subsystem of intercalated Fe ions. It has been shown that this compound exhibits an antiferromagnetic (AF) ground state below the Neel temperature TN = 140 K. Application of the magnetic field at T < TN induces a metamagnetic phase transition to the ferromagnetic (F) state, which is accompanied by the large magnetoresistance effect (up to 27 %). The field-induced AF-F transition is found to be irreversible below ~ 100 K. The magnetization reversal in the metastable F state at low temperatures is accompanied by substantial hysteresis (~ 100 kOe) which is associated with the Ising character of Fe ions.