Current Research

Influence of microstructure on magnetic recording in minerals. 

Magnetic measurements can provide quick, highly sensitive measurements of geologic phenomena from pollution monitoring to dating of tectonic or other events. However, we are limited by our understanding of the effects of composition, microstructure, and interactions between the particles which serve as magnetic recorders. This limitation means large numbers of measurements must be discarded, or worse yet, measurements may be accepted in error leading to unsound interpretations. My work attempts to shed light on fundamental processes that affect magnetic recording in minerals to evaluate them as recorders of magnetic fields on geologic and longer timescales. 

Current aspects of research include:

  • Microstructure in iron-titanium oxides: Iron-titanium oxides are the primary magnetic minerals used in palaeomagnetic measurements, in natural samples they frequently display complex microstructures. Using a suite of samples with a variety of compositions, grain sizes, and internal stresses, I am able to observe the effect of these variables on bulk measurements, and hopefully to expand the range of natural samples that can be used by the geology community.
  • Palaeomagnetic recording in meteorites: Magnetic measurements of meteorites can be used to examine the magnetic behaviour of the Sun and the differentiation of bodies in the proto-planetary disc. I am working to characterise the magnetic carriers in chondrites to distinguish primary signals from other processes that have occurred over their very long history.
  • Techniques to bridge the gap between nanoscale and macroscopic observations: Nanoscale processes such as magnetic domain state and interactions can have a great effect on bulk measurements, so direct observation of these processes is necessary to incorporate their effect into our interpretations. I use techniques such as electron holography (see figure) and scanning SQUID microscopy and attempt to integrate observations from such techniques with nascent bulk measurement techniques such as first-order reversal curves.



Publications: 2006-Present

Last updated on 04-May-12 15:36