Significant reduction of thermomagnetic hysteresis in NdMn 2- x Ag x Si 2 (0 ≤ x ≤ 0.4) alloys

ABSTRACTIn this research, the single-phase tetragon NdMn2-xAgxSi2 (0 ≤ x ≤ 0.4) alloys were prepared. It was found that the phase transition temperature was decreased by evaluating Ag substitution, which was attributed to the enhancement of orbital hybridization. The thermomagnetic hysteresis disappears for x ≥ 0.2. For Δμ0H of 0–7 T, the values of the maximum magnetic entropy change (the relative cooling power) are 22.2 J/kgK (420.7 J/kg), 20.1 J/kgK (500.5 J/kg), 19.9 J/kgK (552.8 J/kg) and 12.0 J/kgK (300.0 J/kg) in NdMn2-xAgxSi2 (x = 0, 0.2, 0.3 and 0.4) alloys. The XPS valence band spectra indicate that the density of electron and the hybridization effect is enhanced by increasing the substitution amount of Ag. This is attributed to the fact that the atomic radius of Ag is larger than that of Mn, resulting in the strengthening of the covalent bond between Ag and Si.KEYWORDS: Non-hystereticmagnetocaloric effectmagnetic phase transitionmagnetic refrigeration Disclosure statementNo potential conflict of interest was reported by the author(s).Data availability statementData will be made available on request.Additional informationFundingThis work was supported by the National Natural Science Foundation of China (grant number 51971056), Fundamental Research Funds for the Central Universities (grant number N2109005 and N2209005), the open funding of the State Key Laboratory for Mechanical Behavior of Materials (grant number 20202206) and State Key Laboratory of Advanced Metals and Materials (grant number 2019-ZD07) and Shenyang Municipal Jiebang-Guashuai Program (grant number 22-316-1-02).