(MICROMAGN) Magnetism and microstructure: from the nanometre to the planetary scale.
Lead Research Organisation:
University of Cambridge
Department Name: Earth Sciences
Abstract
Small particles of magnetic minerals in naturally occurring rocks are able to store information about how the Earth's magnetic field has changed throughout history, over geological timescales. This property results from the sizes, shapes and spacings of the magnetic particles within the minerals. In nature, particles of magnetite with diameters of 100-200 nm are the most efficient carriers of magnetic information. Particles of this size can be formed by the subdivision of much larger particles into a 'microstructure' that consists of a three-dimensional arrangement of small magnetic particles separated by non-magnetic material. The details of such microstructures have a fundamental effect on how different minerals store magnetic information. The proposed research project will use experimental electron microscopy techniques to measure the magnetic properties of several mineral samples. The aim of the work is to understand the relationship between the magnetic properties of the minerals at the nanometre length scale and the macroscopic magnetic properties of the Earth and other planets.
Organisations
Publications
Brok E
(2014)
Experimental evidence for lamellar magnetism in hemo-ilmenite by polarized neutron scattering
in Physical Review B
Church N
(2011)
Low-temperature domain wall pinning in titanomagnetite: Quantitative modeling of multidomain first-order reversal curve diagrams and AC susceptibility DOMAIN WALL PINNING IN TITANOMAGNETITE
in Geochemistry, Geophysics, Geosystems
Harrison R
(2007)
Low-temperature exchange coupling between Fe 2 O 3 and Fe Ti O 3 : Insight into the mechanism of giant exchange bias in a natural nanoscale intergrowth
in Physical Review B
Harrison R
(2013)
A computational model of cation ordering in the magnesioferrite-qandilite (MgFe2O4-Mg2TiO4) solid solution and its potential application to titanomagnetite (Fe3O4-Fe2TiO4)
in American Mineralogist
Harrison R
(2010)
Spin orientation in a natural Ti-bearing hematite: Evidence for an out-of-plane component
in American Mineralogist
Harrison R
(2009)
Magnetic ordering in the ilmenite-hematite solid solution: A computational study of the low-temperature spin glass region
in Geochemistry, Geophysics, Geosystems
Harrison R
(2009)
Mineral Magnetism: Providing New Insights into Geoscience Processes
in Elements
Harrison, R.J. Dunin-Borkowski, R., Kasama, T., Simpson, E.T., Feinberg, J. M.
(2007)
Mineral Physics
Kasama T
(2010)
Direct observation of ferrimagnetic/ferroelastic domain interactions in magnetite below the Verwey transition
in Earth and Planetary Science Letters
McEnroe SA
(2007)
Magnetic exchange bias of more than 1 Tesla in a natural mineral intergrowth.
in Nature nanotechnology