Magnetocrystalline anisotropy of YCo5 and related RECo5 compounds

G. Daalderop, P. Kelly, M. Schuurmans

Research output: Contribution to journalArticleAcademicpeer-review

44 Citations (Scopus)
27 Downloads (Pure)

Abstract

The magnetocrystalline anisotropy energy of Y(Formula presented) has been calculated from first principles using the local-spin-density approximation. The easy magnetization axis is predicted correctly and the anisotropy energy is only 20% smaller than the experimental value if a recently proposed orbital polarization correction is included; otherwise it is about a factor of 7 too small. Our analysis indicates that magnetic materials with substantially larger anisotropy energies than the best available nowadays should be possible. A large orbital moment is found to contribute to the magnetization bringing the calculated moment, 8.0(Formula presented) per Y(Formula presented) unit cell, into good agreement with the experimental value of 8.3(Formula presented). A large anisotropy in the magnetization is calculated which is nearly completely due to an anisotropic orbital moment associated with the Co atoms. The magnetocrystalline anisotropy energy is shown to be strongly correlated with the anisotropy in the total orbital moment. There is a large reduction in the hyperfine fields compared to the value in bulk hcp Co, not only due to large orbital contributions, but also to different values of the valence contact term. The contribution of the rare-earth (RE) ions to the anisotropy energy of the related RE(Formula presented) compounds may be understood in terms of the crystal-field and exchange interactions felt by the localized (Formula presented) electrons. The (Formula presented)-Co exchange interactions and the Hartree contribution to the crystal field have been calculated under the assumption that these interactions may be treated as small perturbations. The electric-field gradient (Formula presented) and the (Formula presented) crystal-field parameter at the RE site are a factor of 2 and 3 larger than the experimental values, respectively. The order of magnitude of the calculated exchange field agrees with the values derived from experiment.

Original languageEnglish
Pages (from-to)14415-14433
Number of pages19
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume53
Issue number21
DOIs
Publication statusPublished - 1 Jan 1996
Externally publishedYes

Fingerprint

Magnetocrystalline anisotropy
Anisotropy
anisotropy
Rare earths
Magnetization
Exchange interactions
Crystals
orbitals
crystal field theory
moments
rare earth elements
Magnetic materials
magnetization
energy
Electric fields
Ions
Polarization
Atoms
interactions
Electrons

Cite this

@article{9a27149fff294b08a4b3b775b7b79617,
title = "Magnetocrystalline anisotropy of YCo5 and related RECo5 compounds",
abstract = "The magnetocrystalline anisotropy energy of Y(Formula presented) has been calculated from first principles using the local-spin-density approximation. The easy magnetization axis is predicted correctly and the anisotropy energy is only 20{\%} smaller than the experimental value if a recently proposed orbital polarization correction is included; otherwise it is about a factor of 7 too small. Our analysis indicates that magnetic materials with substantially larger anisotropy energies than the best available nowadays should be possible. A large orbital moment is found to contribute to the magnetization bringing the calculated moment, 8.0(Formula presented) per Y(Formula presented) unit cell, into good agreement with the experimental value of 8.3(Formula presented). A large anisotropy in the magnetization is calculated which is nearly completely due to an anisotropic orbital moment associated with the Co atoms. The magnetocrystalline anisotropy energy is shown to be strongly correlated with the anisotropy in the total orbital moment. There is a large reduction in the hyperfine fields compared to the value in bulk hcp Co, not only due to large orbital contributions, but also to different values of the valence contact term. The contribution of the rare-earth (RE) ions to the anisotropy energy of the related RE(Formula presented) compounds may be understood in terms of the crystal-field and exchange interactions felt by the localized (Formula presented) electrons. The (Formula presented)-Co exchange interactions and the Hartree contribution to the crystal field have been calculated under the assumption that these interactions may be treated as small perturbations. The electric-field gradient (Formula presented) and the (Formula presented) crystal-field parameter at the RE site are a factor of 2 and 3 larger than the experimental values, respectively. The order of magnitude of the calculated exchange field agrees with the values derived from experiment.",
author = "G. Daalderop and P. Kelly and M. Schuurmans",
year = "1996",
month = "1",
day = "1",
doi = "10.1103/PhysRevB.53.14415",
language = "English",
volume = "53",
pages = "14415--14433",
journal = "Physical review B: Condensed matter and materials physics",
issn = "1098-0121",
publisher = "American Physical Society",
number = "21",

}

Magnetocrystalline anisotropy of YCo5 and related RECo5 compounds. / Daalderop, G.; Kelly, P.; Schuurmans, M.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 53, No. 21, 01.01.1996, p. 14415-14433.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Magnetocrystalline anisotropy of YCo5 and related RECo5 compounds

AU - Daalderop, G.

AU - Kelly, P.

AU - Schuurmans, M.

PY - 1996/1/1

Y1 - 1996/1/1

N2 - The magnetocrystalline anisotropy energy of Y(Formula presented) has been calculated from first principles using the local-spin-density approximation. The easy magnetization axis is predicted correctly and the anisotropy energy is only 20% smaller than the experimental value if a recently proposed orbital polarization correction is included; otherwise it is about a factor of 7 too small. Our analysis indicates that magnetic materials with substantially larger anisotropy energies than the best available nowadays should be possible. A large orbital moment is found to contribute to the magnetization bringing the calculated moment, 8.0(Formula presented) per Y(Formula presented) unit cell, into good agreement with the experimental value of 8.3(Formula presented). A large anisotropy in the magnetization is calculated which is nearly completely due to an anisotropic orbital moment associated with the Co atoms. The magnetocrystalline anisotropy energy is shown to be strongly correlated with the anisotropy in the total orbital moment. There is a large reduction in the hyperfine fields compared to the value in bulk hcp Co, not only due to large orbital contributions, but also to different values of the valence contact term. The contribution of the rare-earth (RE) ions to the anisotropy energy of the related RE(Formula presented) compounds may be understood in terms of the crystal-field and exchange interactions felt by the localized (Formula presented) electrons. The (Formula presented)-Co exchange interactions and the Hartree contribution to the crystal field have been calculated under the assumption that these interactions may be treated as small perturbations. The electric-field gradient (Formula presented) and the (Formula presented) crystal-field parameter at the RE site are a factor of 2 and 3 larger than the experimental values, respectively. The order of magnitude of the calculated exchange field agrees with the values derived from experiment.

AB - The magnetocrystalline anisotropy energy of Y(Formula presented) has been calculated from first principles using the local-spin-density approximation. The easy magnetization axis is predicted correctly and the anisotropy energy is only 20% smaller than the experimental value if a recently proposed orbital polarization correction is included; otherwise it is about a factor of 7 too small. Our analysis indicates that magnetic materials with substantially larger anisotropy energies than the best available nowadays should be possible. A large orbital moment is found to contribute to the magnetization bringing the calculated moment, 8.0(Formula presented) per Y(Formula presented) unit cell, into good agreement with the experimental value of 8.3(Formula presented). A large anisotropy in the magnetization is calculated which is nearly completely due to an anisotropic orbital moment associated with the Co atoms. The magnetocrystalline anisotropy energy is shown to be strongly correlated with the anisotropy in the total orbital moment. There is a large reduction in the hyperfine fields compared to the value in bulk hcp Co, not only due to large orbital contributions, but also to different values of the valence contact term. The contribution of the rare-earth (RE) ions to the anisotropy energy of the related RE(Formula presented) compounds may be understood in terms of the crystal-field and exchange interactions felt by the localized (Formula presented) electrons. The (Formula presented)-Co exchange interactions and the Hartree contribution to the crystal field have been calculated under the assumption that these interactions may be treated as small perturbations. The electric-field gradient (Formula presented) and the (Formula presented) crystal-field parameter at the RE site are a factor of 2 and 3 larger than the experimental values, respectively. The order of magnitude of the calculated exchange field agrees with the values derived from experiment.

UR - http://www.scopus.com/inward/record.url?scp=0000407905&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.53.14415

DO - 10.1103/PhysRevB.53.14415

M3 - Article

VL - 53

SP - 14415

EP - 14433

JO - Physical review B: Condensed matter and materials physics

JF - Physical review B: Condensed matter and materials physics

SN - 1098-0121

IS - 21

ER -