Temperature dependence of magnetic and thermal properties of chiral HyFe and HyMn close to phase transitions by using the Landau mean field model

Abstract

Abstract Magnetic and thermal properties of chiral metal formate frameworks (MOFs) of NH2NH3M(HCOO)3, M = Fe, Mn, namely, HyFe and HyMn are investigated close to phase transitions by using Landau phenomenological model. By expanding the free energy in terms of the order parameter, for magnetic properties the temperature dependence of magnetization and inverse magnetic susceptibility, and for thermal properties the heat capacity and entropy are calculated for chiral HyFe and HyMn close to phase transitions using the experimental data from the literature. Additionally, structural order parameter and inverse susceptibility are predicted from the model, which can be compared with the observed data for chiral HyFe and HyMn. It is found that Landau phenomenological model is adequate to describe the phase transitions in chiral HyFe, and antiferromagnet chiral HyMn.