Formation of ultrathin cobalt ferrite films by interdiffusion of Fe3O4/CoO bilayers
DC Element | Wert | Sprache |
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dc.contributor.author | Rodewald, J. | |
dc.contributor.author | Thien, J. | |
dc.contributor.author | Pohlmann, T. | |
dc.contributor.author | Hoppe, M. | |
dc.contributor.author | Timmer, F. | |
dc.contributor.author | Bertram, F. | |
dc.contributor.author | Kuepper, K. | |
dc.contributor.author | Wollschlaeger, J. | |
dc.date.accessioned | 2021-12-23T16:13:22Z | - |
dc.date.available | 2021-12-23T16:13:22Z | - |
dc.date.issued | 2019 | |
dc.identifier.issn | 24699950 | |
dc.identifier.uri | https://osnascholar.ub.uni-osnabrueck.de/handle/unios/10535 | - |
dc.description.abstract | In this work an alternate pathway is demonstrated to form ultrathin cobalt ferrite (CoxFe3-xO4) films by interdiffusion of Fe3O4/CoO bilayers. Bilayer samples with different Fe3O4/CoO thickness ratios have been prepared by reactive molecular beam epitaxy on Nb-doped SrTiO3(001) substrates to obtain cobalt ferrite films of varied stoichiometry. Subsequently, oxygen-assisted postdeposition annealing experiments for consecutive temperature steps between 300 degrees C and 600 degrees C have been conducted monitoring the interdiffusion process by means of high-resolution x-ray reflectivity, soft and angle-resolved hard x-ray photoelectron, and x-ray absorption spectroscopy. Magnetic properties were characterized using superconducting quantum interference device magnetometry. The interdiffusion process starts from 300 degrees C annealing temperature and is completed for temperatures above 500 degrees C. For completely interdiffused films with Co:Fe ratios larger than 0.84:2 a thin segregated CoO layer on top of the ferrite is formed. This CoO segregation is attributed to surface and interface effects. In addition, multiplet calculations of x-ray absorption spectra are performed to determine the occupancy of different sublattices. These results are correlated with the magnetic properties of the ferrite films. A stoichiometric CoFe2O4 film with partial inversion has been formed exhibiting homogeneously distributed Co2+ and mainly Fe3+ valence states if the initial Co:Fe content is 1.09:2. Thus, for the formation of stoichiometric cobalt ferrite by the proposed postdeposition annealing technique an initial Co excess has to be provided as the formation of a top CoO layer is inevitable. | |
dc.description.sponsorship | Deutsche Forschungsgemeinschaft (DFG)German Research Foundation (DFG) [KU2321/2-1, KU2321/6-1, WO533/20-1]; Financial support from the Deutsche Forschungsgemeinschaft (DFG under Grants No. KU2321/2-1, No. KU2321/6-1, and No. WO533/20-1) is gratefully acknowledged. We thank Diamond Light Source for giving access to beamlines I07 (SI15334-1) and I09 (SI15205-1) and for the great beamline support. Additionally, we would like to acknowledge the assistance at beamline P09 at PETRA III (I-20170258), DESY, where parts of this work were carried out. | |
dc.language.iso | en | |
dc.publisher | AMER PHYSICAL SOC | |
dc.relation.ispartof | PHYSICAL REVIEW B | |
dc.subject | ANODE MATERIAL | |
dc.subject | CATIONIC DISTRIBUTION | |
dc.subject | COFE2O4 | |
dc.subject | FE | |
dc.subject | MAGNETIC-PROPERTIES | |
dc.subject | Materials Science | |
dc.subject | Materials Science, Multidisciplinary | |
dc.subject | OXIDE | |
dc.subject | PHOTOELECTRON ANGULAR-DISTRIBUTION | |
dc.subject | Physics | |
dc.subject | Physics, Applied | |
dc.subject | Physics, Condensed Matter | |
dc.subject | REFLECTION | |
dc.subject | THIN-FILMS | |
dc.subject | X-RAY-ABSORPTION | |
dc.title | Formation of ultrathin cobalt ferrite films by interdiffusion of Fe3O4/CoO bilayers | |
dc.type | journal article | |
dc.identifier.doi | 10.1103/PhysRevB.100.155418 | |
dc.identifier.isi | ISI:000490467600007 | |
dc.description.volume | 100 | |
dc.description.issue | 15 | |
dc.contributor.orcid | 0000-0002-0426-3591 | |
dc.identifier.eissn | 24699969 | |
dc.publisher.place | ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA | |
dcterms.isPartOf.abbreviation | Phys. Rev. B | |
dcterms.oaStatus | hybrid | |
crisitem.author.dept | FB 04 - Physik | - |
crisitem.author.dept | Universität Osnabrück | - |
crisitem.author.deptid | fb04 | - |
crisitem.author.orcid | 0000-0002-0426-3591 | - |
crisitem.author.orcid | 0000-0001-9002-4118 | - |
crisitem.author.parentorg | Universität Osnabrück | - |
crisitem.author.netid | RoJa644 | - |
crisitem.author.netid | BeFl001 | - |
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geprüft am 07.06.2024