Tunable magnetic phase transition and magnetocaloric effect in the rare-earth-free Al-Mn-Fe-Co-Cr high-entropy alloys

Rare‐Earth‐Free Mn30Fe20−xCuxAl50 Magnetocaloric Materials with Stable Cubic CsCl‐Type Structure for Room‐Temperature Refrigeration

“…a) Δ H dependence of TEC (10K), −Δ S M max , RCP, and RC of the Mn 30 Fe 12 Cu 8 Al 50 alloy; b) Δ S M ( T ) curves of Mn 30 Fe 20− x Cu x Al 50 alloys under and Δ H of 0–2 and 0–7 T; and c) the −Δ S M max for Mn 30 Fe 20− x Cu x Al 50 alloys and reported room‐temperature magnetocaloric materials. [ 1–3,42–49 ] …”

“…As expected, the finally constructed MAP curves (Figure 5c) were parallel with each other, and the curve at 300 K passed through the origin using β = 0.386 and γ = 1.273. Finally, we further checked their reliability based on the scaling hypothesis which can be described as follows, [ 48 ] $$$$\begin{equation}M\left( {H,\varepsilon } \right) = {\varepsilon }^\beta f \pm \left( {H/{\varepsilon }^{\beta + \gamma }} \right)\end{equation}$$$$where f + is for ɛ > 0 and f ‐ is for ɛ <0. Equation (13) can be further reduced to m = f±(h) by similarly reconstructing the M ( H ) curves to be m ≡ ɛ − β M ( H , ɛ) and h ≡ ɛ −( β + γ ) H , respectively.…”

“…These values were comparable to those of the RE 1-x A x MnO 3 -based MCMs and their substituted variants, and also better than those of recently reported RE-free magnetocaloric materials with SO-MPT, such as, the Iron-based, Cobaltbased, Manganese-based alloys or compounds as well as the all transition metal-based high-entropy alloys. [1][2][3][42][43][44][45][46][47][48][49] However, they are still obviously smaller than those of pure Gd as well as Gd 5 (Si,Ge) 4 -based and La(Fe,Si) 13 -based giant magnetocaloric materials. [1][2][3] We here should state that it is impossible to achieve such high magnetocaloric performance for 3d transition metalbased MCMs with SO-MPT as the RE-based MCMs, due to fact of much lower magnetic moments of 3D transition metal than those of RE elementals.…”

“…As expected, the finally constructed MAP curves (Figure 5c) were parallel with each other, and the curve at 300 K passed through the origin using 𝛽 = 0.386 and 𝛾 = 1.273. Finally, we further checked their reliability based on the scaling hypothesis which can be described as follows, [48] M (H, 𝜀)…”

Griffiths-like behavior and magnetocaloric properties of rare-earth silicide Tb2Co0.8Si3.2

“…Similarly, RCP is as good as with the materials like Tm 5 Pt 2 In 4 [41], R 2 Ni 2 In (R-Pr, Nd) [42], Dy 11 Co 4 In 9 [43], and R 2 Ni 2 Ga (R = Ho, Tm) [44]. Regarding the TEC, estimated TEC (10 K) of Tb 2 Co 0.8 Si 3.2 is on a par with the TEC of R 5 Pt 2 In 4 (R = Tb, Gd) [41], Fe 7 Se 8 [45], Al 20 Mn 20 Fe 20 Co 14.5+x Cr 25.5−x (x = 0, 1, and 2) [46]. While considering the good magnetocaloric materials in this temperature region (see table 3), the titled compound's magnetocaloric performance is only moderate.…”