Role of interplay of austenite and martensite phase fractions on the magnetocaloric and magnetoresistance effects across the martensite transition in Ni45Mn44Sn7In4 Heusler alloy near room temperature

Abstract

The influence of martensite and austenite phase fractions on the magnetocaloric and magnetoresistance (MR) properties has been studied across the first-order magneto-structural martensite transition in the polycrystalline Ni45Mn44Sn7In4 Heusler alloy near room temperature. Here, we have studied in detail the structural, calorimetric, magnetic, magnetocaloric, and magneto-resistance properties of the Ni45Mn44Sn7In4 Heusler alloy. The detailed investigation of thermal and magnetic field path dependent magnetization and resistivity reveals that In incorporation in the alloy increases the martensite transition (MT) temperature, magnetocaloric effect (MCE), and MR properties of the sample at relatively low magnetic fields near the room temperature. The temperature and magnetic field path dependent austenite phase fraction have been calculated using a theoretical model. A strong correlation between observed MR and field induced austenite phase fraction (fFIA) has been established, which reveals that MR does not depend on the parent austenite and martensite phases. This work explores the fundamental phenomena of the interplay of austenite and martensite phase fractions that contribute to the magnetocaloric effect (MCE) and MR properties in In doped Ni-Mn-Sn compounds very close to room temperature. The maximum MR is found to be −36.2% for the change in the 8 T magnetic field, when fFIA is 73.9% at 313 K. The isothermal magnetic entropy change, refrigeration capacity, and adiabatic temperature change are found to be 17.5 J kg−1 K−1, 100.8 J/kg, and −7.2 K, respectively, for the change in the 5 T magnetic field near 315 K.

Realization of Enhanced Refrigeration Capacity with Non-Hysteretic Behavior in Ni40Gd5Co5Mn37In12Si1 Alloy Near Room Temperature at 2T

“…It is noticed from Figure b,c that the magnetic hysteresis has been reduced with substitution and addition of Gd in Ni 45 Co 5 Mn 37 In 12 Si 1 alloy. The notable reduction in magnetization of GS and GA could be due to the lattice distortion and the presence of the secondary phase in these alloys, which can lead to changes in Mn–Mn distance. ,,,,, As a result of the foregoing, the magnetization (Δ M ) of Gd-substituted and Gd-added alloys decreased as ∼20 and ∼18 emu/g, respectively, whereas the parent alloy’s magnetization is ∼90 emu/g at 2 T.…”

“…The core-level XPS of Ni 2p, Co 2p, Gd 4d, Mn 2p, In 3d, and Si 2p for GA sample was recorded and is presented in Figure . The elemental binding energies of Ni 2p 3/2 (2p 1/2 ), Co 2p 3/2 (2p 1/2 ), Gd 4d 5/2 (4d 3/2 ), Mn 2p 3/2 (2p 1/2 ), In 3d 5/2 (3d 3/2 ), and Si 2p 3/2 (2p 1/2 ) are ∼851.7 eV (∼873.09 eV), ∼779.8 eV (∼796.9 eV),∼140.74 eV (145.81 eV), ∼640.74 eV (∼653.02 eV), ∼443.7 eV (∼451.35 eV), and ∼101.1 eV (∼105.6), respectively, which also confirms that all the constituent elements in Ni 45 Co 5 Mn 37 In 12 Si 1 are their respective metallic states of Ni 2p, Co 2p, Mn 2p, In 3d, and Si 2p, and seen untraceable oxidation during synthesis of alloys, consistent with the previous reports in the literature. − The core-level XPS spectra of Ni 2p, Co 2p, Mn 2p, In 3d, and Si 2p of NM alloy is seen in Figure S3, Supporting Information. To be specific, intensity variation shows that doping Gd in NM alloy plays an important role in the core level as it decreases the intensity of the element.…”

“…The notable reduction in magnetization of GS and GA could be due to the lattice distortion and the presence of the secondary phase in these alloys, which can lead to changes in Mn−Mn distance. 41,53,55,56,60,61 As a result of the foregoing, the magnetization (ΔM) of Gd-substituted and Gd-added alloys decreased as ∼20 and ∼18 emu/g, respectively, whereas the parent alloy's magnetization is ∼90 emu/g at 2 T. Furthermore, it is to be noted that M versus H plot of NM has shown the same path without any magnetic hysteresis from 313 to 343 K upon increasing and decreasing magnetic field upto 2 T. Above 343 K, there is a clear indication of magnetic hysteresis in the temperature range of 363−393 K, as seen in Figure 8a. Nevertheless, this magnetic hysteresis is significantly diminished in the samples of Gd-substituted and Gd-added alloys, as seen in Figure 8b,c.…”

Ni-Mn-Sn-Cu Alloys after Thermal Cycling: Thermal and Magnetic Response

“…In these alloys, the transformations can be induced by mechanical stress, temperature and/or external magnetic field. Functional effects of these materials are: magnetic shape memory [1], magnetocaloric [2], magneto-resistance [3], exchange-bias [4], barocaloric [5] or elastocaloric [6].…”

Direct and Indirect Determination of the Magnetocaloric Effect in the Heusler Compound Ni1.7Pt0.3MnGa

“…This leads to intrinsic irreversibilities in both isothermal entropy and adiabatic temperature changes, which can drastically reduce the cooling efficiency [18][19][20][21]. In order to optimize the cooling efficiency, huge efforts have been made to control the characteristics of the magnetic transition [22,23]. In particular, in NiMnGa, Pt-substitution on the Ni site appears as an excellent route, since one obtains a series of magnetic shape-memory alloys with properties similar to NiMnGa, but with a larger internal strain [2,11,14].…”