Abstract
A study of the effects of interparticle interactions on ordering in ferrofluids have been carried out The techniques employed were Monte Carlo simulation and the Hypernetted Chain approximation from the integral equation theories of fluids. Good agreement was found between the two methods at packing fractions which are typical of ferrofluids both in zero field and a magnetically saturating field. The degree of magnetic ordering giving rise to Curie - Weiss behaviour was found to be smaller in the 3-dimensional model that was studied compared with the 2-dimensional model considered previously.The effects of the repulsive force produced by the surfactant coatings on the particles have been studied both analytically and by computer simulation. Our model indicates that the repulsion is more hard sphere like than that used in previous simulations and our analytical result provides much closer agreement with the computer simulations than previous results.
Further investigation into ordering in ferrofluids was made by considering cluster formation. We have developed a novel method of cluster analysis based on the maximum entropy technique which allows clusters to be identified in a manner which is characteristic of the pair interaction potential that gave rise to them. Finally the possibility of magnetic phase transitions have been considered using a number of theoretical techniques.
| Date of Award | 27 Mar 1992 |
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| Original language | English |
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| Sponsors | Science and Engineering Research Council |