1.2.1.2.11 Galvanomagnetic properties

Bonnenberg, D.; Hempel, K. A.; Wijn, H.P.J.

doi:10.1007/10311893_33

Cited by 2 publications

(2 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, this increase in the orbital magnetic moment is much more significant than that of the spin magnetic moment. As mentioned earlier, due to its incomplete treatment of the 3d electron-electron correlation, the GGA calculations give an orbital moment which is only half of the corresponding experimental value 57 . In contrast, the theoretical orbital moment from the GGA+U calculations with U = 1.6 eV is almost doubled and becomes in rather good agreement with the experimental value (see the results for m//c in Table I).…”

Section: B Spin and Orbital Magnetic Momentsmentioning

confidence: 93%

Anomalous and spin Hall effects in hcp cobalt from GGA+Ucalculations

2012

View full text Add to dashboard Cite

We have calculated the intrinsic anomalous and spin Hall conductivities, spin and orbital magnetic moments and also spin polarization of Hall currents in hexagonal cobalt within the density functional theory with the generalized gradient approximation (GGA) plus on-site Coulomb interaction (GGA+U ). The accurate all-electron full-potential linearized augmented plane wave method is used. We find that the anomalous Hall conductivity (AHC) (σ A xy ) and orbital magnetic moment (mo) of cobalt with the magnetization being along the c-axis (m//c) calculated in the GGA+U scheme with U = 1.6 eV and J = 0.9 eV agree rather well with the corresponding experimental values while, in contrast, the σ A xy and mo from the GGA calculations are significantly smaller than the measured ones. This suggests that moderate U = 1.6 eV and J = 0.9 eV are appropriate for Co metals. The calculated AHC and spin Hall conductivity (SHC) (σ S ) are highly anisotropic, and the ratio of the Hall conductivity for m//c to that for the magnetization being in-plane (m//ab) from the GGA+U calculations, is ∼16.0 for the AHC and ∼6.0 for the SHC. For m//c, the spin-up and spin-down Hall currents are found to flow in the same direction. The magnitude of the calculated Hall current spin polarization (P H ) is large and P H = −0.61. Remarkably, for m//ab, the spin-up and spin-down Hall currents are predicted to flow in the opposite directions. This indicates that the Hall current contains both spin-polarized charge current and pure spin current, resulting in the magnitude of the Hall current spin polarization (P H = −1.59) being larger than 1.0.

show abstract

Section: B Spin and Orbital Magnetic Momentsmentioning

confidence: 93%

Anomalous and spin Hall effects in hcp cobalt from GGA+Ucalculations

2012

View full text Add to dashboard Cite

show abstract

“…It leads to a B 0 equal to 194 GPa at 0 K. The previous calcul ations with coherent potential approximation (CPA) of the Fe 0.5 Ni 0.5 random alloy have given the B 0 value of about 220 GPa [59]. For comparison, the experimental values of B 0 for the Fe 0.5 Ni 0.5 alloy measured at room temperature vary between 165 GPa and 177 GPa [60] and the experimental B 0 values for Fe and Ni are about 170 GPa and 180 GPa, respectively.…”

Section: Bulk Modulusmentioning

confidence: 97%

Ab initiostudy of magnetocrystalline anisotropy, magnetostriction, and Fermi surface of L1₀FeNi (tetrataenite)

Werwiński¹,

Marciniak²

2017

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

The ordered L1 0 FeNi phase (tetrataenite) is recently considered as a promising candidate for the rare-earth free permanent magnets applications. In this work we calculate several characteristics of the L1 0 FeNi, where most of the results come form the fully relativistic full potential FPLO method with the generalized gradient approximation (GGA). A special attention deserves the summary of the magnetocrystalline anisotropy energies (MAE's), the full potential calculations of the anisotropy constant K 3 , and the combined analysis of the Fermi surface and three-dimensional k-resolved MAE. Other calculated parameters presented in this article are the magnetic moments ms and m l , magnetostrictive coefficient λ 001 , bulk modulus B 0 , and lattice parameters. The MAE's summary shows rather big discrepancies between the experimental MAE's from literature and also between the calculated MAE's. The MAE's calculated in this work with the full potential and GGA are equal to 0.47 MJ m −3 from WIEN2k, 0.34 MJ m −3 from FPLO, and 0.23 MJ m −3 from FP-SPR-KKR code. These last results strongly suggest that the value of MAE in GGA is below 0.5 MJ m −3 . It is also expected that this value is significantly underestimated due to the limitations of the GGA. Unfortunately, as other authors suggest, even the MAE equal 1.3 MJ m −3 would be insufficient to raise the L1 0 FeNi from the category of semi-hard magnets. However the L1 0 FeNi has still a potential to improve its MAE by modifications, like e.g. tetragonal strain or alloying. The presented three-dimensional k-resolved map of the MAE combined with the Fermi surface gives a complete picture of the MAE contributions in the Brillouin zone. The calculated Fermi surface consists of closed hole pockets and open sheets. It reflects a four-fold symmetry of the crystal and is closely related to the MAE(k). The analysis of the effects of external factors, like strain, on the k-resolved MAE and Fermi surface should be beneficial in engineering of the hard magnetic properties. The obtained from full potential FP-SPR-KKR method magnetocrystalline anisotropy constants K 2 and K 3 are several orders of magnitude smaller than the MAE/K 1 and equal to -2.0 kJ m −3 and 110 J m −3 , respectively. The calculated partial spin and orbital magnetic moments of the L1 0 FeNi are equal to 2.72 and 0.054 µ B for Fe and 0.53 and 0.039 µ B for Ni atoms, respectively. The calculations of geometry optimization lead to a c/a ratio equal to 1.0036, B 0 equal to 194 GPa, and λ 001 equal to 9.4 × 10 −6 .

show abstract

1.2.1.2.11 Galvanomagnetic properties

Cited by 2 publications

References 15 publications

Anomalous and spin Hall effects in hcp cobalt from GGA+Ucalculations

Anomalous and spin Hall effects in hcp cobalt from GGA+Ucalculations

Ab initiostudy of magnetocrystalline anisotropy, magnetostriction, and Fermi surface of L1₀FeNi (tetrataenite)

Contact Info

Product

Resources

About

1.2.1.2.11 Galvanomagnetic properties

Cited by 2 publications

References 15 publications

Anomalous and spin Hall effects in hcp cobalt from GGA+Ucalculations

Anomalous and spin Hall effects in hcp cobalt from GGA+Ucalculations

Ab initiostudy of magnetocrystalline anisotropy, magnetostriction, and Fermi surface of L10FeNi (tetrataenite)

Contact Info

Product

Resources

About

Ab initiostudy of magnetocrystalline anisotropy, magnetostriction, and Fermi surface of L1₀FeNi (tetrataenite)