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Effect of temperature-dependent shape anisotropy on coercivity for aligned Stoner-Wohlfarth soft ferromagnets
- Source :
- Physical Review B. 75
- Publication Year :
- 2007
- Publisher :
- American Physical Society (APS), 2007.
-
Abstract
- The temperature variation effect of shape anisotropy on the coercivity, HC(T), for the aligned Stoner-Wohlfarth (SW) soft ferromagnets, such as fcc Ni, fcc Co and bcc Fe, are investigated within the framework of Neel-Brown (N-B) analysis. An extended N-B equation is thus proposed,by introducing a single dimensionless correction function, the reduced magnetization, m(\tao) = MS(T)/MS(0), in which \tao = T/TC is the reduced temperature, MS(T) is the saturation magnetization, and TC is the Curie temperature. The factor, m(\tao), accounts for the temperature-dependent effect of the shape anisotropy. The constants, H0 and E0, are for the switching field at zero temperature and the potential barrier at zero field, respectively. According to this newly derived equation, the blocking temperature above which the properties of superparamagnetism show up is described by the expression, TB = E0m^2(\tao)/[kBln(t/t0)], with the extra correction factor m^2(\tao). The possible effect on HC(T) and the blocking temperature, TB, attributed to the downshift of TC resulting from the finite size effect has been discussed also.<br />Comment: 22 pages, 2 figures, 1 table, Accepted by Phys. Rev. B
- Subjects :
- Physics
Condensed Matter - Materials Science
Condensed matter physics
Materials Science (cond-mat.mtrl-sci)
FOS: Physical sciences
Field (mathematics)
Coercivity
Condensed Matter Physics
Electronic, Optical and Magnetic Materials
Magnetization
Magnetic anisotropy
Ferromagnetism
Curie temperature
Anisotropy
Dimensionless quantity
Subjects
Details
- ISSN :
- 1550235X and 10980121
- Volume :
- 75
- Database :
- OpenAIRE
- Journal :
- Physical Review B
- Accession number :
- edsair.doi.dedup.....bdd4f2344c420a9da5f8a6efd0082af0