Uniform magnetic excitations in nanoparticles

Steen Mørup, Britt Rosendahl Hansen

Research output: Contribution to journalJournal articleResearchpeer-review

386 Downloads (Pure)

Abstract

We have used a spin-wave model to calculate the temperature dependence of the (sublattice) magnetization of magnetic nanoparticles. The uniform precession mode, corresponding to a spin wave with wave vector q=0, is predominant in nanoparticles and gives rise to an approximately linear temperature dependence of the (sublattice) magnetization well below the superparamagnetic blocking temperature for both ferro-, ferri-, and antiferromagnetic particles. This is in accordance with the results of a classical model for collective magnetic excitations in nanoparticles. In nanoparticles of antiferromagnetic materials, quantum effects give rise to a small deviation from the linear temperature dependence of the (sublattice) magnetization at very low temperatures. The complex nature of the excited precession states of nanoparticles of antiferromagnetic materials, with deviations from antiparallel orientation of the sublattice magnetization vectors, results in a contribution to the susceptibility, which increases with increasing temperature.
Original languageEnglish
JournalPhysical Review B Condensed Matter
Volume72
Issue number2
Pages (from-to)024418
ISSN0163-1829
DOIs
Publication statusPublished - 2005

Bibliographical note

Copyright 2005 American Physical Society

Cite this

Mørup, Steen ; Hansen, Britt Rosendahl. / Uniform magnetic excitations in nanoparticles. In: Physical Review B Condensed Matter. 2005 ; Vol. 72, No. 2. pp. 024418.
@article{2278a5a3075d492e9046697713e3ef75,
title = "Uniform magnetic excitations in nanoparticles",
abstract = "We have used a spin-wave model to calculate the temperature dependence of the (sublattice) magnetization of magnetic nanoparticles. The uniform precession mode, corresponding to a spin wave with wave vector q=0, is predominant in nanoparticles and gives rise to an approximately linear temperature dependence of the (sublattice) magnetization well below the superparamagnetic blocking temperature for both ferro-, ferri-, and antiferromagnetic particles. This is in accordance with the results of a classical model for collective magnetic excitations in nanoparticles. In nanoparticles of antiferromagnetic materials, quantum effects give rise to a small deviation from the linear temperature dependence of the (sublattice) magnetization at very low temperatures. The complex nature of the excited precession states of nanoparticles of antiferromagnetic materials, with deviations from antiparallel orientation of the sublattice magnetization vectors, results in a contribution to the susceptibility, which increases with increasing temperature.",
author = "Steen M{\o}rup and Hansen, {Britt Rosendahl}",
note = "Copyright 2005 American Physical Society",
year = "2005",
doi = "10.1103/PhysRevB.72.024418",
language = "English",
volume = "72",
pages = "024418",
journal = "Physical Review B (Condensed Matter and Materials Physics)",
issn = "1098-0121",
publisher = "American Physical Society",
number = "2",

}

Uniform magnetic excitations in nanoparticles. / Mørup, Steen; Hansen, Britt Rosendahl.

In: Physical Review B Condensed Matter, Vol. 72, No. 2, 2005, p. 024418.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Uniform magnetic excitations in nanoparticles

AU - Mørup, Steen

AU - Hansen, Britt Rosendahl

N1 - Copyright 2005 American Physical Society

PY - 2005

Y1 - 2005

N2 - We have used a spin-wave model to calculate the temperature dependence of the (sublattice) magnetization of magnetic nanoparticles. The uniform precession mode, corresponding to a spin wave with wave vector q=0, is predominant in nanoparticles and gives rise to an approximately linear temperature dependence of the (sublattice) magnetization well below the superparamagnetic blocking temperature for both ferro-, ferri-, and antiferromagnetic particles. This is in accordance with the results of a classical model for collective magnetic excitations in nanoparticles. In nanoparticles of antiferromagnetic materials, quantum effects give rise to a small deviation from the linear temperature dependence of the (sublattice) magnetization at very low temperatures. The complex nature of the excited precession states of nanoparticles of antiferromagnetic materials, with deviations from antiparallel orientation of the sublattice magnetization vectors, results in a contribution to the susceptibility, which increases with increasing temperature.

AB - We have used a spin-wave model to calculate the temperature dependence of the (sublattice) magnetization of magnetic nanoparticles. The uniform precession mode, corresponding to a spin wave with wave vector q=0, is predominant in nanoparticles and gives rise to an approximately linear temperature dependence of the (sublattice) magnetization well below the superparamagnetic blocking temperature for both ferro-, ferri-, and antiferromagnetic particles. This is in accordance with the results of a classical model for collective magnetic excitations in nanoparticles. In nanoparticles of antiferromagnetic materials, quantum effects give rise to a small deviation from the linear temperature dependence of the (sublattice) magnetization at very low temperatures. The complex nature of the excited precession states of nanoparticles of antiferromagnetic materials, with deviations from antiparallel orientation of the sublattice magnetization vectors, results in a contribution to the susceptibility, which increases with increasing temperature.

U2 - 10.1103/PhysRevB.72.024418

DO - 10.1103/PhysRevB.72.024418

M3 - Journal article

VL - 72

SP - 024418

JO - Physical Review B (Condensed Matter and Materials Physics)

JF - Physical Review B (Condensed Matter and Materials Physics)

SN - 1098-0121

IS - 2

ER -