Structural and electronic properties of Fe(AlxGa1–x)3 system

Mondal, Debashis; Kamal, C.; Banik, Soma; Bhakar, Ashok; Kak, Ajay; Das, Gangadhar; Reddy, V. Krishna; Chakrabarti, Aparna; Ganguli, Tapas

doi:10.1063/1.4965718

Cited by 7 publications

(10 citation statements)

References 25 publications

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“…Because this secondary phase exists as a constant weight percent through all of the scans, we assume that it does not affect the structural transition that we observe in the main phase AlFe 2 B 2 . Moreover, Fe(Ga, Al) 3 is not magnetic, 36 so it does not contribute to the magnetism observed for this sample. The AlFe 2 B 2 structure (inset of Fig.…”

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confidence: 85%

Structural changes upon magnetic ordering in magnetocaloric AlFe2B2

Oey

Bocarsly

Mann

et al. 2020

Applied Physics Letters

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With a Curie temperature just above room temperature, AlFe 2 B 2 is a useful magnetocaloric material composed of earth-abundant elements. We employ temperature-dependent high resolution synchrotron X-ray diffraction to establish with high certainly that the paramagnetic to ferromagnetic transition in AlFe 2 B 2 is second order, showing no discontinuity in lattice parameters or cell volume. Nevertheless, the lattice parameters undergo anisotropic changes across the transition with distinct differences in the thermal expansion coefficients. While the a and b lattice parameters show positive thermal expansion, c shows negative thermal expansion. We link these changes to the respective interatomic distances to determine the contribution of magnetism to the anisotropic structural evolution. The work underpins the possible role of magnetostructural coupling in driving the magnetocaloric effect in AlFe 2 B 2 .

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confidence: 85%

Structural changes upon magnetic ordering in magnetocaloric AlFe2B2

Oey

Bocarsly

Mann

et al. 2020

Applied Physics Letters

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“…A unit cell contains 4 formula units where each Fe has eight Ga neighbors at two distinct sites Ga1 (0.236 nm, 2 atoms) and Ga2 (0.239 nm, 2 atoms and 0.246 nm, 4 atoms, above the plane containing Fe) 2 . Whereas hole doping by Zn at the Ga site or Mn at the Fe site 14 does not induce an insulating-metal transition and introduces ingap states 16 , electron doping either at the Fe or the Ga site destroys the semiconducting behavior, and remarkably influences other physical properties [11][12][13][14][15][16][17][18][19][20][21][24][25][26] .…”

Section: Introductionmentioning

confidence: 99%

Magnetic order of intermetallicFeGa3−yGeystudied byμSRand<

et al. 2017

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Temperature dependent magnetization, muon spin rotation and 57 Fe Mössbauer spectroscopy experiments performed on crystals of intermetallic 0.14, 0.17, 0.22, 0.27, 0.29, 0.32) are reported. Whereas at y = 0.11 even a sensitive magnetic microprobe such as µSR does not detect magnetism, all other samples display weak ferromagnetism with a magnetic moment of up to 0.22 µB per Fe atom. As a function of doping and of temperature a crossover from short range to long range magnetic order is observed, characterized by a broadly distributed spontaneous internal field. However, the y = 0.14 and y = 0.17 remain in the short range ordered state down to the lowest investigated temperature. The transition from short range to long range order appears to be accompanied by a change of the character of the spin fluctuations, which exhibit spin wave excitations signature in the LRO part of the phase diagram. Mössbauer spectroscopy for y = 0.27 and 0.32 indicates that the internal field lies in the plane perpendicular to the crystallographic c axis. The field distribution and its evolution with doping suggest that the details of the Fe magnetic moment formation and the consequent magnetic state are determined not only by the dopant concentration but also by the way the replacement of the Ga atoms surrounding the Fe is accomplished.

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“…It has a tetragonal crystal structure and it belongs to P 4 2 /mnm space group symmetry. 4,[9][10][11] The unit cell has four Fe atoms, arranged in two pairs of dimers. The Fe-Fe distance in the dimer is 2.77 Å, and these dimers are separated from each other by 6.55 Å along c direction.…”

Section: Introductionmentioning

confidence: 99%

“…and are surrounded by Ga atoms. Different indirect measurements, such as temperature dependent resistivity, temperature dependent magnetic susceptibility, a combination of photoelectron spectroscopy (PES) and inverse photoelectron spectroscopy (IPES) measurements, have been carried out to estimate the bandgap of this material, 4,[9][10][11][12][13] and is found to be between 0.3 -0.5 eV. Local moment on the Fe atom in FeGa 3 has been probed by Mossbauer spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

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An experimental and Ab-initio study of Electronic and Magnetic properties of FeGa3

Mondal,

Banik,

Kamal

et al. 2018

Preprint

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Electronic structure of FeGa3 has been studied using experiments and ab-initio calculations. Magnetization measurements show that FeGa3 is inherently diamagnetic in nature. Our studies indicate that the previously reported magnetic moment on the Fe atoms in FeGa3 is not an intrinsic property of FeGa3, but is primarily due to the presence of disorder, defects, grain boundaries etc that break the symmetry about the Fe dimers. Analysis of the results obtained from magnetic measurements, photoelectron spectroscopy, Fe K-edge X-ray absorption near edge spectroscopy and ab-initio calculations clearly indicates that, the effects of on-site Coulomb repulsion between the Fe 3d electrons do not play any role in determining the electronic and magnetic properties of FeGa3. Detailed analysis of results of single crystal and poycrystalline FeGa3, helps to resolve the discrepancy in the electronic and magnetic properties in FeGa3 existing in the literature, consistently.

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Structural and electronic properties of Fe(Al_xGa_1–_x)₃ system

Cited by 7 publications

References 25 publications

Structural changes upon magnetic ordering in magnetocaloric AlFe2B2

Structural changes upon magnetic ordering in magnetocaloric AlFe2B2

Magnetic order of intermetallicFeGa3−yGeystudied byμSRand<

An experimental and Ab-initio study of Electronic and Magnetic properties of FeGa3

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