Effect on Annealing Temperature (Ta) of Ternary Full Fe2CrSi Heusler Alloy Nanoparticles for Spin-Based Device Applications

Heusler alloys present a large group of binary, [1][2][3][4][5] ternary, [6][7][8][9][10] or quaternary [11][12][13][14] compounds with a wide variety of physical properties. [15][16][17][18] Thanks to their extensive tunability [19][20][21][22] based on their chemical composition, crystal, or electronic structure, [23][24][25][26][27][28][29] they attract interest in the fundamental and application approach. [30][31][32][33][34] Particularly, spin polarization, [33,35] superconductivity, [36][37][38][39] shape memory, [40][41][42][43][44][45] or magnetocaloric behavior [28,40,[46][47][48][49][50] have triggered significant interest in the experimental and theoretical perspective.Based on the chemical composition and the resulting properties, Heusler alloys, also known as full-Heusler alloys with the stoichiometry X 2 YZ, can be divided into several groups according to their physical properties. [51] Co 2 YZ-based Heusler can be considered the leading group of materials showing high spin polarization (P) or even half metallicity (P ¼ 100%). [52][53][54][55][56][57] However, theoretical and experimental studies point to the high sensitivity of spin polarization on the structural disorder. [58] Here, the L2 1 crystalline phase exhibits the highest structural ordering, essential for achieving the required spin polarization values. [59] In contrast, while the mutual exchange of the atoms on the Y-Z position (B2 disorder) has a low influence on the spin polarization values, the X-Y or X-Y-Z disorders (D0 3 or A2, respectively) may significantly decrease spin polarization values. [55,60,61] The presented disadvantage can be solved by a suitable chemical composition or a proper method of preparation of Heusler alloys. [62,63] Stoichiometric and off-stoichiometric Ni-Mn-Z- [64][65][66] and Ni-Fe-Z-based Heusler alloys [67][68][69] are well-known magnetocaloric, shape memory, or even magnetic shape memory materials. [70,71] The mentioned Heusler alloys undergo a structural transformation from a low-temperature martensitic phase to a high-temperature austenitic phase, [51,[64][65][66][72][73][74] which may significantly influence the magnetic entropy change ΔS M and the intensity of the magnetocaloric effect. [75,76] Additionally, Heusler alloys consist of cheap elements like Ni, Fe, Mn, Co, Ga, and In, and thus may be considered low-cost counterparts for typical magnetocaloric material based on Gd, Rh, or other rare-earth elements. [77][78][79][80][81] Another advantage of the Ni-Mn-Zand Ni-Fe-Z-based Heusler alloys consists in the tunability of their structural and magnetic properties. Depending on the

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confidence: 99%

Heusler‐Based Cylindrical Micro‐ and Nanowires

Hennel

Varga

Frolova

et al. 2022

Physica Status Solidi (a)

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“…Shorter milling times, in the order 20-30 h, and subsequent annealing at 500-600 • C allowed us to obtain the Heusler Fe 2 CrSi alloy with magnetization of about 55-80 emu/g and coercivity of 30-65 Oe [8,9]. Quite different values of the M S ~64, 68, 59 emu/g and H C ~157, 52, 41 Oe were reported for the Heusler nanoparticle alloy Fe 2 CrSi prepared using the mechanical alloying method in zirconia vial with zirconia balls during 4 h wet milling and subsequently annealed at 700, 800 and 900 • C, respectively [18]. In the case of our studies, the values of M S agree well with the published data; however, the coercivity is relatively smaller.…”

Section: Discussionmentioning

confidence: 99%

Structure and Magnetic Properties of Mechanosynthesized Nanocrystalline Fe2CrSi Heusler Alloy

Jartych,

Jaskółowska,

Oleszak

et al. 2023

Nanomaterials

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Heusler alloys constitute an interesting group of materials with wide applications. The purpose of the present study was to use the mechanical alloying method to synthesize Fe2CrSi Heusler alloy and learn about its structure and magnetic properties. Pure metal elements were ground for various periods of time in a planetary ball mill, and the process of alloy formation was monitored using X-ray diffraction and Mössbauer spectroscopy. It was found that after 20 h of milling, the disordered BCC solid solution was formed, with an average crystallite size ~11 nm. After thermal treatment, the desired Fe2CrSi Heusler alloy was obtained, with a small amount of secondary phases. Detailed XRD analysis showed the coexistence of two varieties of Heusler phase, namely Fm-3m and Pm-3n. The main result of this work is the detection of the hyperfine magnetic field distribution using Mössbauer spectroscopy. The occurrence of this distribution proves atomic disorder in the crystalline structure of the obtained Heusler alloy. Macroscopic magnetic measurements revealed soft magnetic properties of the alloy, with a magnetic moment of ~2.3 μB/f.u., only slightly larger than the theoretically predicted value.

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“…Here, the authors studied the influence of the pH value and composition on physical properties of Co-Fe-Al Heusler nanoparticles. Nehla et al [44] [16,[45][46][47][48]. They all have studied the structural, magnetic, and magnetocaloric properties of the NPs.…”

Section: Introductionmentioning

confidence: 99%