| EPSRC Reference: |
GR/L06225/01 |
| Title: |
RELAXATION TIMES FOR SINGLE-DOMAIN FERROMAGNETIC PARTICLES |
| Principal Investigator: |
Crothers, Professor DSF |
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| Department: |
Applied Maths & Theoretical Physics |
| Organisation: |
Queen's University of Belfast |
| Scheme: |
Standard Research (Pre-FEC) |
| Starts: |
01 October 1997 |
Ends: |
31 December 2000 |
Value (£): |
103,412
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| EPSRC Research Topic Classifications: |
| Magnetism/Magnetic Phenomena |
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Summary on Grant Application Form |
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Single-domain ferromagnetic particles are used in the magnetic-recording industry and in paleomagnetism. Thermal fluctuations cause the internal magnetic field to flip from one stable state to another; thus excessive temperature may cause instability. The internal distribution of magnetic-moment orientations is best described by the Fokker-Planck equation. By separating the variables and Laplace transforming, differential recurrence relations may be established even for asymptotic potentials expressed as a spherical-harmonic expansion. Such particles include those associated with external oblique magnetic fields, dipole-dipole interactions and cubic anisotropy, positive or negative. The time-evolution of the internal magnetic field and the critical correlation and relaxation times may all be parametrised by the eigenvalues and eigenfunctions of an infinite matrix derived from the recurrence relations. Truncation of the matrix can lead to severe instability in the calculation, especially for large barrier heights. The latest diagonalisers and multiprecision techniques will be adapted to solve this problem. In addition, the multidimensional application of the method of steepest descent will be used to complement the physical understanding of the exact solutions. The ultimate goal is to assist the magnetic-recording industry, which includes Seagate Technology Ltd, London/derry.
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Key Findings |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Potential use in non-academic contexts |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Impacts |
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| Description |
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk |
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Sectors submitted by the Researcher |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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| Project URL: |
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| Further Information: |
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| Organisation Website: |
http://www.qub.ac.uk |