First-principles relativistic study of spin waves in thin magnetic films

Research output: Contribution to journalArticle

117 Citations (Scopus)

Abstract

In order to study spin-wave excitations of itinerant ferromagnets a relativistic first-principles method based on the adiabatic approach is presented. The derivatives of the free energy up to second order with respect of the polar and azimuthal angles are derived within the framework of the magnetic force theorem and the fully relativistic Korringa-Kohn-Rostoker method. Exchange and spin-orbit coupling are thus incorporated on equal footing in the Hamiltonian. Furthermore, a detailed comparison to classical spin Hamiltonians is given and it is shown that the magnetocrystalline anisotropy energy contains contributions from both the on-site anisotropy and the off-site exchange coupling terms. The method is applied to an Fe monolayer on Cu(001) and Au(001) surfaces and for a Co monolayer on Cu(001). The calculations provide with the gap at zero wave number due to the spin-orbit coupling and uniaxial anisotropy energies in good agreement with the results of the band energy difference method. It is pointed out that the terms in the spin-wave Hamiltonian related to the mixed partial derivatives of the free energy, absent within a nonrelativistic description, introduce an asymmetry in the magnon spectrum with respect to two in-plane easy axes. Moreover, in the case of an in-plane magnetized system the long-wavelength magnons are elliptically polarized due to the difference of the second-order uniaxial and fourth-order in-plane magnetic anisotropy.

Original languageEnglish
Article number104436
Pages (from-to)1044361-10443611
Number of pages9399251
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume68
Issue number10
Publication statusPublished - Sep 2003

Fingerprint

Magnetic thin films
Hamiltonians
Spin waves
magnetic films
magnons
anisotropy
Free energy
Monolayers
Orbits
Anisotropy
Derivatives
Magnetocrystalline anisotropy
Exchange coupling
Magnetic anisotropy
free energy
orbits
Band structure
wave excitation
energy bands
Wavelength

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

First-principles relativistic study of spin waves in thin magnetic films. / Udvardi, L.; Szunyogh, L.; Palotás, K.; Weinberger, P.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 68, No. 10, 104436, 09.2003, p. 1044361-10443611.

Research output: Contribution to journalArticle

@article{47f5d0e19f3b4e70b026f605d28b8ed6,
title = "First-principles relativistic study of spin waves in thin magnetic films",
abstract = "In order to study spin-wave excitations of itinerant ferromagnets a relativistic first-principles method based on the adiabatic approach is presented. The derivatives of the free energy up to second order with respect of the polar and azimuthal angles are derived within the framework of the magnetic force theorem and the fully relativistic Korringa-Kohn-Rostoker method. Exchange and spin-orbit coupling are thus incorporated on equal footing in the Hamiltonian. Furthermore, a detailed comparison to classical spin Hamiltonians is given and it is shown that the magnetocrystalline anisotropy energy contains contributions from both the on-site anisotropy and the off-site exchange coupling terms. The method is applied to an Fe monolayer on Cu(001) and Au(001) surfaces and for a Co monolayer on Cu(001). The calculations provide with the gap at zero wave number due to the spin-orbit coupling and uniaxial anisotropy energies in good agreement with the results of the band energy difference method. It is pointed out that the terms in the spin-wave Hamiltonian related to the mixed partial derivatives of the free energy, absent within a nonrelativistic description, introduce an asymmetry in the magnon spectrum with respect to two in-plane easy axes. Moreover, in the case of an in-plane magnetized system the long-wavelength magnons are elliptically polarized due to the difference of the second-order uniaxial and fourth-order in-plane magnetic anisotropy.",
author = "L. Udvardi and L. Szunyogh and K. Palot{\'a}s and P. Weinberger",
year = "2003",
month = "9",
language = "English",
volume = "68",
pages = "1044361--10443611",
journal = "Physical Review B-Condensed Matter",
issn = "0163-1829",
publisher = "American Physical Society",
number = "10",

}

TY - JOUR

T1 - First-principles relativistic study of spin waves in thin magnetic films

AU - Udvardi, L.

AU - Szunyogh, L.

AU - Palotás, K.

AU - Weinberger, P.

PY - 2003/9

Y1 - 2003/9

N2 - In order to study spin-wave excitations of itinerant ferromagnets a relativistic first-principles method based on the adiabatic approach is presented. The derivatives of the free energy up to second order with respect of the polar and azimuthal angles are derived within the framework of the magnetic force theorem and the fully relativistic Korringa-Kohn-Rostoker method. Exchange and spin-orbit coupling are thus incorporated on equal footing in the Hamiltonian. Furthermore, a detailed comparison to classical spin Hamiltonians is given and it is shown that the magnetocrystalline anisotropy energy contains contributions from both the on-site anisotropy and the off-site exchange coupling terms. The method is applied to an Fe monolayer on Cu(001) and Au(001) surfaces and for a Co monolayer on Cu(001). The calculations provide with the gap at zero wave number due to the spin-orbit coupling and uniaxial anisotropy energies in good agreement with the results of the band energy difference method. It is pointed out that the terms in the spin-wave Hamiltonian related to the mixed partial derivatives of the free energy, absent within a nonrelativistic description, introduce an asymmetry in the magnon spectrum with respect to two in-plane easy axes. Moreover, in the case of an in-plane magnetized system the long-wavelength magnons are elliptically polarized due to the difference of the second-order uniaxial and fourth-order in-plane magnetic anisotropy.

AB - In order to study spin-wave excitations of itinerant ferromagnets a relativistic first-principles method based on the adiabatic approach is presented. The derivatives of the free energy up to second order with respect of the polar and azimuthal angles are derived within the framework of the magnetic force theorem and the fully relativistic Korringa-Kohn-Rostoker method. Exchange and spin-orbit coupling are thus incorporated on equal footing in the Hamiltonian. Furthermore, a detailed comparison to classical spin Hamiltonians is given and it is shown that the magnetocrystalline anisotropy energy contains contributions from both the on-site anisotropy and the off-site exchange coupling terms. The method is applied to an Fe monolayer on Cu(001) and Au(001) surfaces and for a Co monolayer on Cu(001). The calculations provide with the gap at zero wave number due to the spin-orbit coupling and uniaxial anisotropy energies in good agreement with the results of the band energy difference method. It is pointed out that the terms in the spin-wave Hamiltonian related to the mixed partial derivatives of the free energy, absent within a nonrelativistic description, introduce an asymmetry in the magnon spectrum with respect to two in-plane easy axes. Moreover, in the case of an in-plane magnetized system the long-wavelength magnons are elliptically polarized due to the difference of the second-order uniaxial and fourth-order in-plane magnetic anisotropy.

UR - http://www.scopus.com/inward/record.url?scp=0142184885&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0142184885&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0142184885

VL - 68

SP - 1044361

EP - 10443611

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 0163-1829

IS - 10

M1 - 104436

ER -