Negative magnetocaloric effect in Fe 1-x Rh x compounds

Mohamed Balli (1) , Daniel Fruchart (1) , Damien Gignoux , A. Yekini

1 NEEL - MNM - Micro et NanoMagnétisme

On increasing temperature, the Fe1-xRhx alloys present a transition from an antiferromagnetic to a ferromagnetic state, which induces a negative magnetocaloric effect (MCE). The magnetocaloric effect, in particular of the Fe0.49Rh0.51 alloy, was studied by direct measurements and according to specific heat measurements. Here, we report the recent results obtained on the annealed Fe0.48Rh0.52 compound we prepared by arc melting. The isothermal entropy change ΔS allowing an estimation of the MCE was determined from magnetic measurements. The ΔS experimentally found is larger than that reported for the annealed Fe0.49Rh0.51 sample. However a significant difference occurs between transition temperature of the annealed sample Fe0.48Rh0.52 and that reported in literature. This result shows that magnetic and magnetocaloric properties in this kind of materials are very sensitive to the technique of samples preparation. Besides, the magnetocaloric effect close the ferromagnetic – paramagnetic transition in Fe0.48Rh0.52 is also discussed.

Mots clés: effect magnétocalorique; matériaux magnétocaloriques; réfrigération magnétique

Domaines: Matière Condensée [cond-mat]

Mohamed Balli, Daniel Fruchart, Damien Gignoux, A. Yekini. Negative magnetocaloric effect in Fe 1-x Rh x compounds. Second IIF-IIR International Conference on Magnetic Refrigeration at Room Temperature, Apr 2007, Portoroz, Slovenia. ⟨hal-01185993⟩