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
Magnetic and mechanical effects of Mn substitutions in AlFe2B2
Show others and affiliations
(English)Manuscript (preprint) (Other academic)
National Category
Inorganic Chemistry
Identifiers
URN: urn:nbn:se:uu:diva-331787OAI: oai:DiVA.org:uu-331787DiVA: diva2:1150532
Available from: 2017-10-19 Created: 2017-10-19 Last updated: 2017-10-20
In thesis
1. Magnetic Materials for Cool Applications: Relations between Structure and Magnetism in Rare Earth Free Alloys
Open this publication in new window or tab >>Magnetic Materials for Cool Applications: Relations between Structure and Magnetism in Rare Earth Free Alloys
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

New and more efficient magnetic materials for energy applications are a big necessity for sustainable future. Whether the application is energy conversion or refrigeration, materials based on sustainable elements should be used, which discards all rare earth elements. For energy conversion, permanent magnets with high magnetisation and working temperature are needed whereas for refrigeration, the entropy difference between the non-magnetised and magnetised states should be large. For this reason, magnetic materials have been synthesised with high temperature methods and structurally and magnetically characterised with the aim of making a material with potential for large scale applications. To really determine the cause of the physical properties the connections between structure (crystalline and magnetic) and, mainly, the magnetic properties have been studied thoroughly.

The materials that have been studied have all been iron based and exhibit properties with potential for the applications in mind. The first system, for permanent magnet applications, was Fe5SiB2. It was found to be unsuitable for a permanent magnet, however, an interesting magnetic behaviour was studied at low temperatures. The magnetic behaviour arose from a change in the magnetic structure which was solved by using neutron diffraction. Substitutions with phosphorus (Fe5Si1-xPxB2) and cobalt (Fe1-xCox)5PB2 were then performed to improve the permanent magnet potential. While the permanent magnetic potential was not improved with cobalt substitutions the magnetic transition temperature could be greatly controlled, a real benefit for magnetic refrigeration. For this purpose AlFe2B2 was also studied, and there it was found, conclusively, that the material undergoes a second order transition, making it unsuitable for magnetic cooling. However, the magnetic structure was solved with two different methods and was found to be ferromagnetic with all magnetic moments aligned along the crystallographic a-direction. Lastly, the origin of magnetic cooling was studied in Fe2P, and can be linked to the interactions between the magnetic and atomic vibrations.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2017. 70 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1585
Keyword
Magnetism, Diffraction, X-ray scattering, Neutron Scattering, Permanent magnets, Magnetocalorics
National Category
Organic Chemistry
Research subject
Chemistry with specialization in Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-331762 (URN)978-91-513-0123-5 (ISBN)
Public defence
2017-12-08, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:00 (English)
Opponent
Supervisors
Available from: 2017-11-16 Created: 2017-10-20 Last updated: 2017-11-16

Open Access in DiVA

No full text

Inorganic Chemistry

Search outside of DiVA

GoogleGoogle Scholar

Total: 15 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