Tailoring the magnetocaloric, magnetic and thermal properties of Dy6(Fe,Mn)X2 intermetallics (X Sb, Te, Bi)

The structural, magnetic, magnetocaloric (MCE) and thermal properties of seven Fe2P-type Dy6(Fe,Mn)X2 (XSb, Bi, Te) intermetallics (space group P6¯2m, N 189, hP9) have been experimentally studied. They present a paramagnetic to ferromagnetic transition (in the range 129–370 K), followed, as temperature decreases, by spin-reorientation one (from 52 170 K) ground magnetic state at 2 K with antiferromagnetic components. This turns into when field is applied. critical exponents β,γ,δ related PM-FM point long order interactions but in most compounds their values severely deviate from Mean Field class, presenting an unconventional behavior, probably due magnetocrystalline anisotropies. complexity has consequence that every intermetallic three MCE effects arise: Two direct (DMCE) table-like effect between 40 more than 400 moderate entropy maxima (up 6.9 J/kgK for μ0ΔH = 5 T, tableau in-between being around 4 J/kgK, Dy6FeSb2 Dy6FeSbTe). calculation Thermal Average Entropy Change allows place two (Dy6FeSb2 Dy6FeSbTe) close other rare earth based high alloys described literature. relevant third MCE, inverse, below 25 K, value 17.8 (μ0ΔH T) Dy6FeSbTe. maximum change Curie shown scale found universal curves built. Finally, diffusivities DMCE measured, result they good (between 1 3 mm2/s) be used real refrigeration systems.