Direct measurement of the magnetocaloric effect in cementite

• The magnetocaloriceffect of Fe3C was investigated at its Curie temperature of 475 K.
• First direct measurement of adiabatic temperature change in cementite.
• ΔTad=1.77 K and ΔS=3.07 J K−1 kg−1 in 2 T.
• MCE follows H2/3 dependence typical for second order phase transition.
• Possible applications include magnetic refrigeration and heat power conversion.

Measurements of the magnetocaloric effect of cementite at its Curie temperature of 475 K are presented. An adiabatic temperature change of 1.76±0.01 K was measured using a direct measurement technique. The isothermal entropy change was determined from measurements of magnetisation isotherms and was shown to be 3.07 J K−1 kg−1 in a field change of 2 T. The field dependencies of both magnetocaloric properties follow the H2/3 dependence typical for ferromagnetic materials with a second order phase transition. The material may be of interest in magnetocaloric applications such as magnetic refrigeration or thermomagnetic power generation.

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