Magnetocaloric effect in {[Fe(pyrazole)4]2[Nb(CN)8]⋅4H2O}n molecular magnet is reported. It crystallizes in tetragonal I41/a space group. The compound exhibits a phase transition to a long range magnetically ordered state at Tc≈8.3 K. The magnetic entropy change ΔSM as well as the adiabatic temperature change ΔTad due to applied field change μ0ΔH=0.1, 0.2, 0.5, 1, 2, 5, 9 T as a function of temperature have been determined by the relaxation calorimetry measurements. The maximum value of ΔSM for μ0ΔH=5 T is 4.9 J mol−1 K−1 (4.8 J kg−1 K−1) at 10.3 K. The corresponding maximum value of ΔTad is 2.0 K at 8.9 K. The temperature dependence of the exponent n characterizing the field dependence of ΔSM has been estimated. It attains the value of 0.64 at the transition temperature, which is consistent with the 3D Heisenberg universality class.
@article{arxiv.1312.0744,
title = {Magnetocaloric effect in {[Fe(pyrazole)$_4$]$_2$[Nb(CN)$_8$]$\cdot$4H$_2$O}$_n$ molecular magnet},
author = {R. Pelka and P. Konieczny and P. M. Zielinski and T. Wasiutynski and Y. Miyazaki and A. Inaba and D. Pinkowicz and B. Sieklucka},
journal= {arXiv preprint arXiv:1312.0744},
year = {2013}
}