Calorimetric observation of the effect of non-magnetic organic cation (A) on the magnetic properties of A[FeIIFeIII(ox)3], A=N(n-C3H7)4+ or N(n-C4H9)4+

Effects of the non-magnetic organic cation A (=N(n-C3H7)4+ and N(n-C4H9)4+) on the magnetic properties of the molecule-based materials A[FeIIFeIII(ox)3] have been studied using the heat capacity calorimetry. In the case of ferrimagnetic N(n-C3H7)4[FeIIFeIII(ox)3] the magnetic phase transition was detected at 38 K along with a small hump around 10 K. The estimated magnetic entropy indicated that the small heat capacity hump around 10 K has magnetic origin. The results have been compared with those of N(n-C4H9)4[FeIIFeIII(ox)3] to clarify the effect of the two different non-magnetic organic cations on the magnetic properties at low temperatures. The low temperature heat capacity humps observed commonly in both the compounds, though at different temperatures, seem to have the same origin.