Defect Engineering: Electron-Exchange Integral Manipulation to Generate a Large Magnetocaloric Effect in Ni₄₁Mn₄₃Co₆Sn₁₀ Alloys

Abstract

A promising magnetocaloric effect has been obtained in Ni–(Co)–Mn–X (X = Sn, In, Sb)-based Heusler alloys, but the low isothermal magnetic entropy change ΔS M restricts the further promotion of such materials. Defect engineering is a useful method to modulate magnetic performance and shows great potential in improving the magnetocaloric effect. In this work, dense Ni vacancies are introduced in Ni41Mn43Co6Sn10 alloys by employing high-energy electron irradiation to adjust the magnetic properties. These vacancies bring about intense lattice distortion to change the distance between adjacent magnetic atoms, leading to a significant enhancement of the average magnetic moment. As a result, the saturation magnetization of ferromagnetic austenite is accordingly improved to generate a high isothermal magnetic entropy change ΔS M of 20.0 J/(kg K) at a very low magnetic field of ∼2 T.

High-pressure synthesis, spin-glass behaviour, and magnetocaloric effects in FexTi2S4 heideite sulphides

“…This result is possibly because the magnetic field can facilitate the inverse transformation process, which increases or decreases the critical temperature. 50 At H = 7 T, the maximum value of entropy change −Δ S max M was 1.54, 1.70, and 2.13 J kg −1 K −1 for the x = 0.24, 0.32 and 0.42 samples, respectively. These −Δ S max M values are lower than that observed for the CdCr 2 S 4 spinel of 7.04 J kg −1 K −1 (at 5 T); 2 however, it is very close or greater than for other sulphides such as α-Gd 2 S 3 (0.1 J kg −1 K −1 ) 19 and Co 0.2 Cu 0.8 Cr 2 S 4 (2.05 J kg −1 K −1 ).…”

“…Moreover, the temperature corresponding to the peak ΔS M increased for x = 0.24 and x = 0.42 samples, while decreased for x = 0.32 sample as the magnetic field increased. This result is possibly because the magnetic field can facilitate the inverse transformation process, which increases or decreases the critical temperature 50 . At H = 7 T, the maximum value of entropy change -𝛥𝑆 𝑚𝑎𝑥 𝑀 was 1.54, 1.70, and 2.13 J.kg -1 .K -1 for the x = 0.24, 0.32 and 0.42 samples, respectively.…”

Structural, magnetic and magnetocaloric properties in distorted RE 2NiTiO6 double perovskite compounds

“…As a result, a large number of theoretical and experimental researches have been carried out on a variety of MR materials. Up to now, a series of MR materials with potential application near ambient temperature have been identified, such as Gd-Si-Ge [6], La-Fe-Si/Al [7], Mn-Fe-P-As/Ge/Si [8,9], and Ni-Mn-X (X = Ga, In and Sn) [10,11], etc. In comparison, rare earth (RE)-based compounds and oxides are regarded as the promising cryogenic MR materials for MR technology on account of their unique advantages and application prospects in the liquefaction of extremely low-temperature resources including helium (He), hydrogen (H 2 ) and nitrogen (N 2 ) [12][13][14][15][16].…”

Magneto-Structural Transition and Refrigeration Property in All-D-Metal Heusler Alloys: A Critical Review

“…Heusler alloys, first discovered by Fritz Heusler in 1903, have attracted much attention due to their unique physical and chemical properties. Currently, Heuslertype alloys are promising candidate materials for various fields, such as actuation [1], energy conversion [2][3][4], refrigeration [5][6][7][8][9][10][11][12], catalysis [13,14] and so on [15][16][17][18][19][20].…”