Design of efficient magnetocaloric materials for energy conversion

The magnetocaloric effect (MCE) is a magneto-thermodynamic phenomenon in which a temperature change of a material is caused by exposing the material to a changing magnetic field under adiabatic conditions. There are two main applications based on the MCE. One application is magnetic refrigeration, which can expel heat in a magnetic field cycle....

Magnetocaloric effect in the (Mn,Fe)₂(P,Si) system: From bulk to nano

In the field of nanoscale magnetocaloric materials, novel concepts like micro-refrigerators, thermal switches, microfluidic pumps, energy harvesting devices and biomedical applications have been proposed. However, reports on nanoscale (Mn,Fe)₂(P,Si)-based materials, which are one of the most promising bulk materials for solid-state...

Magnetic phase diagram of the mn_x fe_2−x p_1−y si_y system

The phase diagram of the magnetocaloric Mn_x Fe_2−x P_1−y Si_y quaternary compounds was established by characterising the structure, thermal and magnetic properties in a wide range of compositions (for a Mn fraction of 0.3 ≤ x < 2.0 and a Si fraction of 0.33 ≤ y ≤ 0.60). The highest ferromagnetic...

Giant magnetocaloric effect for (Mn, Fe, V)2(P, Si) alloys with low hysteresis

The Fe₂P type Mn–Fe–P–Si alloys exhibit a giant magneto-elastic first-order transition, but the large hysteresis limits their performance. Crystal structure evolution and magnetocaloric performance were investigated by varying the Mn and Fe contents at a constant V substitution of 0.02 in Fe₂P-type (Mn_1.17-xFe...

Investigating the Parameter-Driven Cathode Gas Diffusion of PEMFCs with a Piecewise Linearization Model

Improving mass transfer in gas diffusion layers is critical to achieving high-performance proton-exchange membrane fuel cells (PEMFCs). Leaks through the interface between the gas and the membrane electrode assembly frame have been widely investigated, and the controllability of the cathode gas diffusion has not been achieved in most studies....

Ultra-low Hysteresis in Giant Magnetocaloric Mn_1-xV_xFe_0.95(P,Si,B) Compounds

Large thermal hysteresis in the (Mn,Fe)2(P,Si) system hinders an efficient heat exchange and thus limits the magnetocaloric applications. Substitution of manganese by vanadium in the Mn1-x1Vx1Fe0.95P0.593Si0.33B0.077 and Mn1-x2Vx2Fe0.95P0.563Si0.36B0.077 compounds enable a significant reduction in the thermal hysteresis without losing the giant...

Tuning the magneto-elastic transition of (Mn,Fe,V)₂(P,Si) alloys to low magnetic field applications

The first-order magneto-elastic transition in the Mn–Fe–P–Si alloys can be tailored by vanadium substitution. Alloys with a suitable V substitution provide an excellent magnetocaloric effect with minor hysteresis in low magnetic fields up to 1.2 T. Mössbauer measurements show that the hyperfine field is reduced by V substitution. Neutron...

Combined effect of annealing temperature and vanadium substitution for mangetocaloric Mn_1.2-xV_xFe_0.75P_0.5Si_0.5 alloys

Approaching the border of the first order transition and second order transition is significant to optimize the giant magnetocaloric materials performance. The influence of vanadium substitution in the Mn_1.2-xV_xFe_0.75P_0.5Si_0.5 alloys is investigated for annealing temperatures of 1323,...

Reversible low-field magnetocaloric effect in Ni-Mn-In-based Heusler alloys

Ni-Mn-X (X = In, Sn, and Sb) based Heusler alloys show a strong potential for magnetic refrigeration owing to their large magnetocaloric effect (MCE) associated with first-order magnetostructural transition. However, the irreversibility of the MCE under low field change of 0–1 T directly hinders its application as an efficient magnetic coolant....