HR: 15:30h
AN: GP33A-06 INVITED     [Abstracts]
TI: Nanofabrication: A Novel Toolbox for Producing Well Defined, Synthetic Magnetic Minerals for the Study of Magnetic Interactions
AU: * Krasa, D
EM: david.krasa@ed.ac.uk
AF: University of Edinburgh, School of GeoSciences, Grant Institute, King's Buildings, Edinburgh, EH9 3JW, United Kingdom
AU: Williams, W
EM: wyn.williams@ed.ac.uk
AF: University of Edinburgh, School of GeoSciences, Grant Institute, King's Buildings, Edinburgh, EH9 3JW, United Kingdom
AU: Wilkinson, C D
EM: c.wilkinson@elec.gla.ac.uk
AF: University of Glasgow, Department of Electronics & Electrical Engineering, Rankine Building, Oakfield Avenue, Glasgow, G12 8LT, United Kingdom
AB: Magnetostatic interactions between or within individual magnetic mineral grains can severely affect the ability of rocks to faithfully record the direction and intensity of the geomagnetic field. The influence of magnetostatic interactions on palaeomagnetic data is dependent primarily on the distance between individual magnetic mineral particles, the particle size as well as their shape. A systematic study of interactions therefore requires samples with well specified geometries. The use of natural samples is hampered by the fact that grain size, shape, and spacing display broad distributions in most rocks or mineral intergrowths. Conventional synthetic samples in the form of powders are also only of limited use because magnetostatic interactions between individual particles cause clumping. It is thus almost impossible to disperse magnetic mineral powders in a nonmagnetic matrix and thus to set a certain average grain spacing. The use of nanofabrication techniques allows us to produce synthetic magnetic mineral samples where particle size, shape and spacing can be defined with a hitherto unattained precision. In this presentation, an overview of techniques such as electron beam lithography, nanoimprint lithography, and reactive ion etching will be given. We use these techniques to produce two- dimensional arrays of magnetite particles in the size range of tens to hundreds of nanometers, i.e. straddling the SD to PSD size range. More importantly, individual particles can be positioned at will, and any given intergrain spacing can thus be set. First measurements of magnetic hysteresis loops and FORCs on these samples will be presented and the influence of magnetostatic interactions on magnetic granulometry parameters will be discussed.
DE: 1500 GEOMAGNETISM AND PALEOMAGNETISM
DE: 1519 Magnetic mineralogy and petrology
DE: 1540 Rock and mineral magnetism
DE: 1594 Instruments and techniques
DE: 3625 Petrography, microstructures, and textures
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Joint Assembly