Exploring magnetocaloric effect of coordination polymer based on Mn(II) and Nb(IV) by relaxation calorimetry.

Magnetocaloric properties of {MnII 2 (imH) 2 (H 2 O) 4 [NbIV(CN) 8 ]·4H 2 O} n molecular magnet are reported. The coordination polymer crystallizes in the monoclinic P 2 1 / c space group and displays a magnetic second-order phase transition at T c ≈ 24.1 K. The relaxation calorimetry measurements are analyzed in order to determine the temperature dependence of the magnetic entropy change Δ S M as well as the adiabatic temperature change Δ T ad for an array of applied field changes ranging from 0 to 9 T. For μ 0 Δ H = 5 T the entropy change Δ S M attains the maximum value of 6.55 J K−1 mol−1 (9.5 J K−1 kg−1) at 25.5 K, while the corresponding maximum value of Δ T ad amounts to 2.02 K at 25.1 K. The critical behavior of the isothermal entropy change is discussed. In particular, the analysis of the field dependence of Δ S M in terms of the power law implies that the studied compound belongs to the mean-field universality class. • Magnetocaloric effect of manganese octacyanidoniobate is comprehensively reported. • Relaxation calorimetry is employed to get insight into the MCE properties. • Isothermal magnetic entropy and adiabatic temperature changes are determined. • Critical scaling universality class of the compound is suggested. [ABSTRACT FROM AUTHOR]