Abstract
In the present work, single-crystalline quasi-van der Waals ferromagnet Fe0.26TaS2 was successfully synthesized with Fe atoms intercalated at ordered positions between TaS2 layers. Its critical behavior was systematically studied by measuring the magnetization around ferromagnetic to paramagnetic phase transition temperature, T-C similar to 100.7K, under different magnetic fields. The critical exponent beta for the spontaneous magnetization below T-C,gamma for the inverse initial susceptibility above T-C, and delta for the magnetic isotherm at T-C were determined with modified Arrott plots, the Kouvel-Fisher method, the Widom scaling law, and critical isotherm analysis, and found to be the following values: beta = 0.459(6), gamma = 1.205(11), and delta = 3.69(1). The obtained critical exponents are self-consistent and follow the scaling equation, indicating the reliability and intrinsicality of these parameters. A close analysis within the framework of renormalization group theory reveals that the spin coupling inside Fe0.26TaS2 crystal is of the three-dimensional Heisenberg ({d : n} = {3 : 3}) type with long-range magnetic interaction and that the exchange interaction decays with distance as J(r) similar to r(-4.71).