uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Magnetism of Fe/V and Fe/Co multilayers
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Theoretical Magnetism.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Theoretical Magnetism.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Theoretical Magnetism.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Theoretical Magnetism.
Show others and affiliations
2003 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 15, no 5, S599-S615 p.Article in journal (Refereed) Published
Abstract [en]

We discuss in this paper the magnetic and structural parameters of Fe/V and Fe/Co multilayers. The electronic structure, magnetic moments (spin and orbital) and Curie temperatures as well as the magneto-crystalline anisotropy are calculated using first principles theory. Although theory is fairly successful in reproducing the experimental data we argue that the observed difference between theory and experiment most likely is due to lattice imperfections and that the interface between e.g. Fe and V is not perfectly sharp. We also present a model, based on the theory of elasticity, for analysing the structural properties of multilayers.

Place, publisher, year, edition, pages
2003. Vol. 15, no 5, S599-S615 p.
National Category
Physical Sciences
Identifiers
URN: urn:nbn:se:uu:diva-94289DOI: 10.1088/0953-8984/15/5/313OAI: oai:DiVA.org:uu-94289DiVA: diva2:168090
Available from: 2006-04-12 Created: 2006-04-12 Last updated: 2012-03-27Bibliographically approved
In thesis
1. A Theoretical Study of Magnetism in Nanostructured Materials
Open this publication in new window or tab >>A Theoretical Study of Magnetism in Nanostructured Materials
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

A first-principles linear scaling real-space method for investigating non-collinear magnetic behaviour of nanostructured materials has been developed. With this method, the magnetic structures of small supported transition metal clusters have been examined. The geometric constraints imposed on the clusters by the underlying surface is found to cause non-collinear behaviour for V, Cr, and Mn clusters on Cu(111). Fe clusters supported on Cu and Ni have been studied and both spin and orbital moments are found to be enhanced for the Fe atoms, which is attributed to the recuced symmetry present at the surface. Atoms in Co clusters have been found to order antiferromagnetically, and some times in a non-collinear fasion, when deposited on a W surface. Small clusters of fcc Fe embedded in Cu have been examined and a new type of ordering, not present in larger fcc Fe systems was found.

Several theoretical studies of Fe and Co based nanostructures consisting of multilayers or embedded clusters have been conducted, with the aim of predicting high moment materials for use in data storage applications. In agreement with previous experiments an enhancement of the magnetic moment is found compared to the magnetic moment of bcc Fe. The enhancement has been shown to be caused by increased spin moments for Fe atoms in close proximity with Co atoms, and this enhancement depends on the number of Co neighbours. As a result of these studies, a possible method of increasing the magnetic moment of cluster based materials has been proposed.

Fermi surface analysis have been performed both on bulk materials, in order to investigate mechanisms for stabilizing non-collinear magnetic states, and in layered structures where the effect of the Fermi surface on the interlayer exchange coupling has been investigated.

In addition to the development of a real-space electronic structure method for non-collinear magnetism, a density matrix purification method has been implemented in the framework of linear muffin-tin orbitals.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2006. x + 78 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 167
Keyword
Physics, magnetism, clusters, non-collinear, multilayers, first-principles theory, electronic structure, high-moment materials, exchange interactions, linear scaling methods, Fysik
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-6763 (URN)91-554-6527-7 (ISBN)
Public defence
2006-05-05, Polhemsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2006-04-12 Created: 2006-04-12 Last updated: 2012-03-27Bibliographically approved
2. Electronic Structure and Statistical Methods Applied to Nanomagnetism, Diluted Magnetic Semiconductors and Spintronics
Open this publication in new window or tab >>Electronic Structure and Statistical Methods Applied to Nanomagnetism, Diluted Magnetic Semiconductors and Spintronics
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis is divided in three parts. In the first part, a study of materials aimed for spintronics applications is presented. More specifically, calculations of the critical temperature in diluted magnetic semiconductors (DMS) and half-metallic ferromagnets are presented using a combination of electronic structure and statistical methods. It is shown that disorder and randomness of the magnetic atoms in DMS materials play a very important role in the determination of the critical temperature.

The second part treats materials in reduced dimensions. Studies of multilayer and trilayer systems are presented. A theoretical model that incorporates interdiffusion in a multilayer is developed that gives better agreement with experimental observations. Using Monte Carlo simulations, the observed magnetic properties in the trilayer system Ni/Cu/Co at finite temperatures are qualitatively reproduced.

In the third part, electronic structure calculations of complex Mn-based compounds displaying noncollinear magnetism are presented. The calculations reproduce with high accuracy the observed magnetic properties in these compounds. Furthermore, a model based on the electronic structure of the necessary conditions for noncollinear magnetism is presented.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2005. x+70 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 32
Keyword
Materials science, spintronics, magnetism, Monte Carlo, critical temperature, exchange interactions, percolation, disorder, noncollinear, electronic structure, Materialvetenskap
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-5732 (URN)91-554-6202-2 (ISBN)
Public defence
2005-04-29, Room 4001, Ångströmlaboratoriet, 10:15
Opponent
Supervisors
Available from: 2005-04-08 Created: 2005-04-08 Last updated: 2013-06-20Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Eriksson, OlleBergqvist, LarsBergman, AndersHjörvarsson, BjörgvinNordström, Lars

Search in DiVA

By author/editor
Eriksson, OlleBergqvist, LarsBergman, AndersHjörvarsson, BjörgvinNordström, Lars
By organisation
Theoretical MagnetismDepartment of Physics
In the same journal
Journal of Physics: Condensed Matter
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 589 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf