Magnetocaloric effect in [Fe(pyrazole)₄]₂[Nb(CN)₈]·4H₂Oₙ molecular magnet

الأصل · EN

Magnetocaloric effect in [Fe(pyrazole)₄]₂[Nb(CN)₈]·4H₂Oₙ 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.