Probing the skyrmion phase of MnSi through the field-exponent of the isothermal entropy change

Le résumé fourni par la source

A detailed study of the field-induced entropy change evolution under hydrostatic pressure ( p ) of the well-known skyrmion-hosting MnSi system was carried with the goal of assessing its magnetocaloric properties and identifying the skyrmion phase. The pressure-induced modification of the first-order phase transition boundary of the skyrmion phase in MnSi has been determined through the field-exponent, n ( T , B ) , of the isothermal entropy change [ Δ S α ( B ) n ] . The skyrmion phase boundaries generated from n ( T , B ) and ac-susceptibility data are in qualitatively good agreement at . The application of hydrostatic pressure can lower the transition temperature of MnSi towards the hydrogen liquefaction temperature (∼20 K) while retaining the first-order nature of the phase transition up to the highest applied pressure of p = 9.8 kbar . As a result, the studied system maintains good magnetocaloric properties near 20 K [ | Δ S | = 4.24 J / kg K , adiabatic temperature change | Δ T ad | = 4.62 K (estimated), and refrigerant capacity | R C | = 91.37 J / kg for Δ B = 7 T with p = 9.8 kbar ] , which are comparable to those of light rare-earth Laves phase compounds with the added benefit of being composed of cheap and abundant elements.

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