Suppression of the Verwey Transition by Charge TrappingShow others and affiliations
2018 (English)In: Annalen der Physik, ISSN 0003-3804, E-ISSN 1521-3889, Vol. 530, no 3, article id 1700363Article in journal (Refereed) Published
Abstract [en]
The Verwey transition in Fe3O4 nanoparticles with a mean diameter of 6.3 nm is suppressed after capping the particles with a 3.5 nm thick shell of SiO2. By X-ray absorption spectroscopy and its associated X-ray magnetic circular dichroism this suppression can be correlated to localized Fe2+ states and a reduced double exchange visible in different site-specific magnetization behavior in high magnetic fields. The results are discussed in terms of charge trapping at defects in the Fe3O4/ SiO2 interface and the consequent difficulties in the formation of the common phases of Fe3O4. By comparison to X-ray absorption spectra of bare Fe3O4 nanoparticles in course of the Verwey transition, particular changes in the spectral shape could be correlated to changes in the number of unoccupied d states for Fe ions at different lattice sites. These findings are supported by density functional theory calculations.
Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2018. Vol. 530, no 3, article id 1700363
Keywords [en]
magnetite, nanoparticles, Verwey transition, X-ray absorption spectroscopy
National Category
Condensed Matter Physics
Identifiers
URN: urn:nbn:se:oru:diva-66576DOI: 10.1002/andp.201700363ISI: 000428350500010Scopus ID: 2-s2.0-85042457108OAI: oai:DiVA.org:oru-66576DiVA, id: diva2:1197571
Note
Funding Agencies:
BMBF 05 ES3XBA/5
DFG WE 2623/3-1
Helmholtz Association (Young Investigator's Group Borderline Magnetism) VH-NG-1031
2018-04-132018-04-132018-09-04Bibliographically approved