Influence of Fe-substitution on structural, magnetic and magnetocaloric properties of Nd2Fe17-Co solid solutions

Bouchaala, Noussa; Jemmali, M.; Bartoli, T.; Nouri, K.; Hentech, I.; Walha, Siwar; Bessaïs, L.; Salah, Abdelhamid Ben

doi:10.1016/j.jssc.2017.11.011

Cited by 19 publications

(8 citation statements)

References 68 publications

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“…Intermetallic single crystals of compositions, Er 6 Fe 1 7.6 6 Al 5.34 C 0.65 [38], GdFe 0.37 Ge 2 , GdFe 0.27 Ge 2 [39], ErFe 2.4 Al 0.6 [40] and polycrystalline SmNi 2 [41], SmNi 5 [42], Gd 2 Fe 17-x Cu x [43], Nd 2 Fe 17 -x Co x [44], Er 6 Fe 23-x Al x [45], SmNi 2 Fe [46], SmNi 3-…”

Section: Synthesis By Arc Furnacementioning

confidence: 99%

Polycrystalline Powder Synthesis Methods

Jemmali¹,

Marzougui²,

Smida³

et al. 2022

Crystallization and Applications

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The synthesis of polycrystalline powder is a key step for materials sciences. In this chapter, we present the well-known methods of preparation of powders such as: solid-state reaction, sol–gel, hydrothermal, combustion, co-precipitation. Moreover, synthesis methods by arc furnace, by heating in a “high frequency” induction furnace and by high energy grinding are presented. The obtained powders could be defined by their purity, gain size, crystallinity, and morphology, which are influenced by the synthesis method. In addition, each method is dependent on some parameters like pH, concentration and temperature.

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Section: Synthesis By Arc Furnacementioning

confidence: 99%

Polycrystalline Powder Synthesis Methods

Jemmali¹,

Marzougui²,

Smida³

et al. 2022

Crystallization and Applications

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“…For Sm 2 Fe 17 based systems, on the one hand, the substitution of Fe by Ga, Si or Mo has a positive impact on the properties (2)(3)(4). On the other hand, in the case of Nd 2 Fe 17 , a recent work showed that the magnetic properties can be greatly improved by the substitution of Fe by Co (5).…”

Section: Introductionmentioning

confidence: 99%

“…For Sm 2 Fe 17 -based systems, on the one hand, the substitution of Fe by Ga, Si, or Mo has a positive impact on the properties. 2−4 On the other hand, in the case of Nd 2 Fe 17 , a recent work showed that the magnetic properties can be greatly improved by the substitution of Fe by Co. 5 Furthermore, on the route to Sm 2 Fe 17 synthesis, if the annealing temperature is lower than 800 °C, an out-ofequilibrium (metastable) hexagonal phase (TbCu 7 prototype, P6/mmm) is obtained. This hexagonal phase often presents improved magnetic properties compared to the high-temperature ordered phase thanks to a slightly improved anisotropy.…”

Section: ■ Introductionmentioning

confidence: 99%

“…3 However, in other similar cases (M = Zr, Cr, and Mo), the preferred substitution site is 6c. 4,10 Several structural studies were also done on Nd 2 Fe 17−x Co x , giving mixed results between 18h and 9d as site occupancies for Co. 5,11,12 Furthermore, previous works involving X-ray studies on compounds with the TbCu 7 prototype such as metastable SmFe 9−y Ga y and SmFe 9−y Si y concluded in the substitution of Fe on the 3g site. 6,7 However, in the case of Co−Fe−Sm compounds, precise determination of the substitution sites has never been done before.…”

Section: ■ Introductionmentioning

confidence: 99%

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Site Occupancy Determination in Th₂Zn₁₇- and TbCu₇-types Sm₂Fe_17–xCo_x Compounds using Synchrotron Resonant Diffraction

et al. 2021

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Sm 2 Fe 17 compounds are high performance permanent magnets. Cobalt substitution allows to further improve their magnetic properties. Depending on the thermal treatment cobalt substituted compounds can be synthesized either in the TbCu 7 (disordered) or in the Th 2 Zn 17 (ordered) structure type. Rietveld refinement of the number of transition metal dumbbells replacing rare earth atoms from synchrotron powder diffraction data shows that the TbCu 7 disordered structure has the same composition as the ordered one (transition metal to rare earth ratio equal to 8.5). Then cobalt site occupancies have been determined in both structures using synchrotron resonant (anomalous) diffraction. Cobalt is found to be absent from the dumbbell sites. The diffraction results are confirmed by Mössbauer spectroscopy.

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“…Calculated lattice constants of R2Fe17 and ThMn12type RFe12 phases compared with experimental data at room temperature obtained from Refs [22,24,[55][56][57][58][59]…”

mentioning

confidence: 99%

Lattice dynamics effects on finite-temperature stability of $R_{1-x}$Fe$_{x}$ ($R$ = Y, Ce, Nd, Sm, and Dy) alloys from first principles

Xing,

Ishikawa,

Miura

et al. 2021

Preprint

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We report the effects of lattice dynamics on thermodynamic stability of binary R1−xFex (0 < x < 1) compounds (R: rare-earth elements, Y, Ce, Nd, Sm, and Dy) at finite temperature predicted by first-principles calculation based on density functional theory (DFT). We first demonstrate that the thermodynamic stability of R1−xFex (0 < x < 1) alloys cannot be predicted accurately by the conventional approach, where only the static DFT energy at T = 0 K is used. This issue can be overcome by considering the entropy contribution, including electronic and vibrational free energies, and we obtained convex hull plots at finite temperatures that successfully explain the thermodynamic stability of various known compounds. Our systematic calculation indicates that vibrational entropy helps stabilize various R1−xFex compounds with increasing temperature. In particular, experimentally reported R2Fe17 compounds are predicted to become thermodynamically stable above ∼800 K. We also show that thermodynamic stability is rare-earth dependent and discuss its origin. Besides the experimentally reported structures, the stability of two new monoclinic RFe12 structures found by Ishikawa et al. [Phys. Rev. Mater. 4, 104408 (2020)] based on a genetic algorithm are investigated. These monoclinic phases are found to be dynamically stable and have larger magnetization than the ThMn12-type RFe12. Although they are thermodynamically unstable, the formation energies decrease significantly with increasing temperature, indicating the possibility of synthesizing these compounds at high temperatures.

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Influence of Fe-substitution on structural, magnetic and magnetocaloric properties of Nd2Fe17-Co solid solutions

Cited by 19 publications

References 68 publications

Polycrystalline Powder Synthesis Methods

Polycrystalline Powder Synthesis Methods

Site Occupancy Determination in Th₂Zn₁₇- and TbCu₇-types Sm₂Fe_17–xCo_x Compounds using Synchrotron Resonant Diffraction

Lattice dynamics effects on finite-temperature stability of $R_{1-x}$Fe$_{x}$ ($R$ = Y, Ce, Nd, Sm, and Dy) alloys from first principles

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Influence of Fe-substitution on structural, magnetic and magnetocaloric properties of Nd2Fe17-Co solid solutions

Cited by 19 publications

References 68 publications

Polycrystalline Powder Synthesis Methods

Polycrystalline Powder Synthesis Methods

Site Occupancy Determination in Th2Zn17- and TbCu7-types Sm2Fe17–xCox Compounds using Synchrotron Resonant Diffraction

Lattice dynamics effects on finite-temperature stability of $R_{1-x}$Fe$_{x}$ ($R$ = Y, Ce, Nd, Sm, and Dy) alloys from first principles

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Site Occupancy Determination in Th₂Zn₁₇- and TbCu₇-types Sm₂Fe_17–xCo_x Compounds using Synchrotron Resonant Diffraction