Elastic constants of polycrystalline <i>L</i>1-FePt at high temperatures

Nakamura, Nobutomo; Yoshimura, Naozumi; Ogi, Hirotsugu; Hirao, Masahiko

doi:10.1063/1.4819974

Cited by 8 publications

(3 citation statements)

References 25 publications

(42 reference statements)

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“…It is also recognized that the decrease of the bulk modulus is demonstrated by a solid rhombus. Since both the values and temperature dependencies of bulk modulus reproduce the experimental results [37] with reasonable accuracy, we expect that the lattice softening effects on disorder-L1 0 phase equilibria is well introduced in this paper. We should point out, however, that more sophisticated vibrational free energy beyond quasiharmonic approximation is necessary for the systematic study of thermal properties above the Debye temperature, which is a future subject.…”

Section: B Lattice Thermal Propertiessupporting

confidence: 59%

Synthetic first-principles studies from phase equilibria to microstructural formation in the Fe-Pt L10 phase

et al. 2023

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Electronic-structure calculations, the cluster-variation method of statistical mechanics, and the phase-field method were combined in attempted first-principles calculations of phase equilibria and microstructural evolution associated with the disorder-L1 0 transition of the Fe-Pt system. The calculated disorder-L1 0 transition temperature was within ∼10 K difference from the experimental value, and the locus of spinodal ordering temperature is placed in the phase diagram. The calculated microstructure demonstrates preferential growth of the ordered domain along the <100> direction and, in the later period, an anisotropic morphology of an antiphase domain structure develops. We offered an interpretation from the atomistic point of view for this morphology. We therefore achieved consistent first-principles multiscale calculations of phase equilibria and microstructural evolution, bridging microscopic to mesoscopic scales without any adjusting parameters.

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Section: B Lattice Thermal Propertiessupporting

confidence: 59%

Synthetic first-principles studies from phase equilibria to microstructural formation in the Fe-Pt L10 phase

et al. 2023

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“…Similar observations are reported by MacLaren et al [45] on the P4/mmm-FePt alloy. Moreover, using the Blackman diagram, Nakamura et al showed that P4/mmm-FePt exhibits a tendency toward covalent bond characteristics [46]. Furthermore, we note that the Pm-3m-FePt 3 system shows a trivial shallow pseudogap slightly below the Fermi energy, suggesting relative stability for this system.…”

Section: Density Of Statesmentioning

confidence: 48%

Compositional Dependence of Magnetocrystalline Anisotropy, Magnetic Moments, and Energetic and Electronic Properties on Fe-Pt Alloys

2022

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This work reported the first-principles calculations for the compositional dependence of the energetic, electronic, and magnetic properties of the bimetallic Fe-Pt alloys at ambient conditions. These hybrid alloys have gained substantial attention for their potential industrial applications, due to their outstanding magnetic and structural properties. They possess high magnetocrystalline anisotropy, density, and coercivity. Four Fe-Pt alloys, distinguished by compositions and space groups, were considered in this study, namely P4/mmm-FePt, I4/mmm-Fe3Pt, Pm-3m-Fe3Pt, and Pm-3m-FePt3. The calculated heats of formation energies were negative for all Fe-Pt alloys, demonstrating their stability and experimentally higher formation probability. The P4/mmm-FePt alloy had the lowest magnetic moment, leading to durable magnetic hardness, which made this alloy the most suitable for permanent efficient magnets, and magnetic recording media applications. Moreover, it possessed a relatively large magnetocrystalline anisotropy energy value of 2.966 meV between the in-plane [100] and easy axis [001], suggesting an inside the plane isotropy.

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“…These results qualitatively agree with the existing experimental data: Fe bulk modulus measured at 300 K is equal to B 0Fe = 166.2 GPa 45 while Pt experimental bulk modulus at 300 K is equal to B 0Pt = 280 GPa 46 . Finally, a bulk modulus for FePt polycrystalline L1 0 structure recently measured at room temperature is equal to B 0FePt = 208.1 GPa 47 .…”

Section: Resultsmentioning

confidence: 90%

First-principles calculations on Fe-Pt nanoclusters of various morphologies

Platonenko

Piskunov

Bocharov

et al. 2017

Sci Rep

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Bimetallic FePt nanoparticles with L1 0 structure are attracting a lot of attention due to their high magnetocrystalline anisotropy and high coercivity what makes them potential material for storage of ultra-high density magnetic data. FePt nanoclusters are considered also as nanocatalysts for growth of carbon nanotubes of different chiralities. Using the DFT-LCAO CRYSTAL14 code, we have performed large-scale spin-polarized calculations on 19 different polyhedral structures of FePt nanoparticles in order to estimate which icosahedral or hcp-structured morphology is the energetically more preferable. Surface energy calculations of all aforementioned nanoparticles indicate that the global minimum corresponds to the nanocluster possessing the icosahedron “onion-like” structure and Fe43Pt104 morphology where the outer layer consists of Pt atoms. The presence of the Pt-enriched layer around FePt core explains high oxidation resistance and environmental stability, both observed experimentally.

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Elastic constants of polycrystalline L1-FePt at high temperatures

Cited by 8 publications

References 25 publications

Synthetic first-principles studies from phase equilibria to microstructural formation in the Fe-Pt L10 phase

Synthetic first-principles studies from phase equilibria to microstructural formation in the Fe-Pt L10 phase

Compositional Dependence of Magnetocrystalline Anisotropy, Magnetic Moments, and Energetic and Electronic Properties on Fe-Pt Alloys

First-principles calculations on Fe-Pt nanoclusters of various morphologies

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