Atxitia, U., Hinzke, D., Chubykalo-Fesenko, O., Nowak, U., Kachkachi, H., Mryasov, O.N., Evans, R.F. and Chantrell, R.W. (2010) Multiscale modeling of magnetic materials: Temperature dependence of the exchange stiffness. Physical Review B (PRB). -. ISSN 1098-0121
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Abstract
For finite-temperature micromagnetic simulations the knowledge of the temperature dependence of the exchange stiffness plays a central role. We use two approaches for the calculation of the thermodynamic exchange parameter from spin models: (i) based on the domain-wall energy and (ii) based on the spin-wave dispersion. The corresponding analytical and numerical approaches are introduced and compared. A general theory for the temperature dependence and scaling of the exchange stiffness is developed using the classical spectral density method. The low-temperature exchange stiffness A is found to scale with magnetization as m(1.66) for systems on a simple cubic lattice and as m(1.76) for an FePt Hamiltonian parametrized through ab initio calculations. The additional reduction in the scaling exponent, as compared to the mean-field theory (A similar to m(2)), comes from the nonlinear spin-wave effects.
| Item Type: | Article |
|---|---|
| Copyright, Publisher and Additional Information: | © 2009 American Physical Society. This is an author produced version of a paper published in PHYSICAL REVIEW B. Uploaded in accordance with the publisher's self archiving policy. |
| Keywords: | GREEN FUNCTION THEORY, HEISENBERG-FERROMAGNET, SYSTEMS, NANOSTRUCTURES, EQUATION, FEPT |
| Academic Units: | The University of York > Physics (York) |
| Depositing User: | Repository Administrator York |
| Date Deposited: | 18 Nov 2010 16:16 |
| Last Modified: | 01 May 2013 23:00 |
| Published Version: | http://dx.doi.org/10.1103/PhysRevB.82.134440 |
| Status: | Published |
| Refereed: | Yes |
| Related URLs: | |
| URI: | http://eprints.whiterose.ac.uk/id/eprint/42658 |
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