Magnetic Properties and Mössbauer Spectroscopy for Complex Fe(tpa)(NCS)₂

The studies of Mössbauer spectroscopy and magnetic properties for complex Fe(tpa)(NCS)₂ exhibit that low spin → high spin (HS) transition may be thermally induced. The impurities such as HS-Fe²⁺ residue and HS-Fe³⁺, that were caused by compound preparation, play a significant role in the investigation of spin transition curve. The Mössbauer spectroscopy is used to observe the impurities as separated forms from the spin transition phase directly, and the magnetic susceptibility measurement is used to determine the total paramagnetism from all HS phases. With these two useful tools, an exact spin transition curve was defined by removing the magnetic contribution of the impurities.