Spin orientation in natural nanoscale intergrowths and the origin of giant exchange bias

DOI

The orientation of spins in a natural sample of Ti-bearing hematite (Fe2O3) has been measured previously from 2-300K using neutron powder diffraction. It was shown that spins are tilted out of the basal plane by an average angle of 30°, contrary to the expectation that all spins lie in the basal plane due to suppression of the Morin transition by Ti. This unusual result is thought to be related to ~1 nm exsolution lamellae of ilmenite (FeTiO3), observed using transmission electron microscopy. It is suggested that the exsolution lamellae lead to a localisation of Fe2+ species within the lamellar interfaces, which cause tilting of some spins towards the crystallographic c axis. Here we propose to verify this result by comparing natural and synthetic samples with and without nanoscale lamellae, and study the variation in the spin orientation on heating to above the Néel temperature.

Identifier
DOI https://doi.org/10.5286/ISIS.E.24088043
Metadata Access https://icatisis.esc.rl.ac.uk/oaipmh/request?verb=GetRecord&metadataPrefix=oai_datacite&identifier=oai:icatisis.esc.rl.ac.uk:inv/24088043
Provenance
Creator Dr Richard Harrison; Mr Erik Brok; Dr Suzanne McEnroe; Professor Kim Lefmann
Publisher ISIS Neutron and Muon Source
Publication Year 2014
Rights CC-BY Attribution 4.0 International; https://creativecommons.org/licenses/by/4.0/
OpenAccess true
Contact isisdata(at)stfc.ac.uk
Representation
Resource Type Dataset
Discipline Photon- and Neutron Geosciences
Temporal Coverage Begin 2011-10-12T08:27:47Z
Temporal Coverage End 2011-10-17T04:52:17Z