Calculation of Magnetization and Magnetic Susceptibility Close to Magnetic Phase Transitions in (CH3)2NH2FeIIINiII(HCOO)6 and (CH3)2NH2FeIIICuII(HCOO)6

Abstract

We study the temperature and magnetic field dependence of the magnetization ( $$ M $$ ) and the inverse susceptibility (χ−1) in the metal–organic frameworks, in particular, for (CH3)2NH2FeIIINiII(HCOO)6 (DMFeNi) and (CH3)2NH2FeIIICuII(HCOO)6 (DMFeCu) close to their magnetic phase transitions. The Landau phenomenological model is employed to analyze the experimental data for the $$ M\left( {T, H} \right) $$ from the literature and to calculate χ−1(T, H) of DMFeNi and DMFeCu. Our results indicate that the thermodynamic model studied explains adequately the observed behavior of $$ M\left( {T, H} \right) $$ for DMFeNi and DMFeCu, which exhibit a weakly first-order (or nearly second order) magnetic phase transition.