57Fe Mossbauer spectroscopy study of the correlation between the Fe3+ content and the magnetic properties of natural Cr-spinels

Waerenborgh, João C.; Figueiras, Jorge; A., Mateus; A. Gonçalves, Mário

Publication

57Fe Mossbauer spectroscopy study of the correlation between the Fe3+ content and the magnetic properties of natural Cr-spinels

2002Journal article

dc.contributor.author	Waerenborgh, João C.
dc.contributor.author	Figueiras, Jorge
dc.contributor.author	A., Mateus
dc.contributor.author	A. Gonçalves, Mário
dc.date.accessioned	2022-08-02T09:27:22Z
dc.date.available	2022-08-02T09:27:22Z
dc.date.issued	2002
dc.description.abstract	Both the Fe oxidation degree and the magnetic properties determined by 57Fe Mössbauer spectroscopy were used to characterize the Cr-spinels from the Beja-Acebuches Ophiolite Complex (SE Portugal). Two different types of Cr-spinel were observed. The first one has an average Fe3+/(Fe total) ≈ 25%, and corresponds to unaltered Cr-spinel grains which remain paramagnetic down to 6K. The second one results from the alteration of the first type, has an average Fe3+/(Fe total) ≈40% and order magnetically between 222 K and 78 K. Fe3+/(total Fe) increases with the magnetic ordering temperature. The grain population ordering at the highest temperatures, in the range 202–222K, has the highest Fe3+/(total Fe) ≈ 58%. Quantitative Fe site distributions can be obtained from room-temperature Mössbauer data if the different recoilless factors for tetrahedral Fe2+ and octahedral Fe3+ are considered. The observed second-order Doppler shifts are consistent with Mössbauer temperatures of 330K and 605K, reported in the literature for tetrahedral Fe2+ and octahedral Fe3+ in other oxide spinels. The differences in the magnetic ordering temperatures allowed the characterization of both types of Cr-spinels using a single Mössbauer absorber, thus avoiding the need to separate them physically, which, in this case, would be very difficult. The results are compared to those obtained for other Cr-spinels and, for the first time in the case of natural Cr-spinels, the increase of their magnetic ordering temperatures with their oxidation degree, resulting from natural processes, is discussed in terms of the magnetic exchange interactions between the Fe cations.	pt_PT
dc.description.version	info:eu-repo/semantics/publishedVersion	pt_PT
dc.identifier.doi	10.1127/0935-1221/2002/0014-0437	pt_PT
dc.identifier.uri	http://hdl.handle.net/10451/54002
dc.language.iso	eng	pt_PT
dc.peerreviewed	yes	pt_PT
dc.publisher	Copernicus Publications	pt_PT
dc.relation	PBICT/P/CTA/2112/95	pt_PT
dc.relation.publisherversion	https://pubs.geoscienceworld.org/eurjmin/article-abstract/14/2/437/61934/57Fe-Mo-ssbauer-spectroscopy-study-of-the?redirectedFrom=fulltext	pt_PT
dc.rights.uri	http://creativecommons.org/licenses/by/4.0/	pt_PT
dc.subject	Mössbauer spectroscopy	pt_PT
dc.subject	Beja-Acebuches Ophiolite Complex	pt_PT
dc.title	57Fe Mossbauer spectroscopy study of the correlation between the Fe3+ content and the magnetic properties of natural Cr-spinels	pt_PT
dc.type	journal article
dspace.entity.type	Publication
oaire.citation.endPage	446	pt_PT
oaire.citation.issue	2	pt_PT
oaire.citation.startPage	437	pt_PT
oaire.citation.title	European Journal of Mineralogy	pt_PT
oaire.citation.volume	14	pt_PT
person.familyName	Nunes Mateus
person.familyName	Carreira Gonçalves
person.givenName	António Manuel
person.givenName	Mário Abel
person.identifier	D-3727-2011
person.identifier	B-4751-2008
person.identifier.ciencia-id	3012-5AFF-429F
person.identifier.ciencia-id	DB18-804D-DAB7
person.identifier.orcid	0000-0003-2623-1539
person.identifier.orcid	0000-0002-1898-0727
person.identifier.scopus-author-id	6701374691
person.identifier.scopus-author-id	7202320464
rcaap.rights	openAccess	pt_PT
rcaap.type	article	pt_PT
relation.isAuthorOfPublication	48cb5c2a-66a8-4389-a848-80813db2c9b0
relation.isAuthorOfPublication	73f9d07d-0de8-4500-8908-9722df62dba5
relation.isAuthorOfPublication.latestForDiscovery	48cb5c2a-66a8-4389-a848-80813db2c9b0