Calculating the spontaneous magnetization and defining the Curie temperature using a positive-feedback model
- Department of Electronics, Carleton University, Ottawa, Ontario K1S 5B6 (Canada)
A positive-feedback mean-field modification of the classical Brillouin magnetization theory provides an explanation of the apparent persistence of the spontaneous magnetization beyond the conventional Curie temperature—the little understood “tail” phenomenon that occurs in many ferromagnetic materials. The classical theory is unable to resolve this apparent anomaly. The modified theory incorporates the temperature-dependent quantum-scale hysteretic and mesoscopic domain-scale anhysteretic magnetization processes and includes the effects of demagnetizing and exchange fields. It is found that the thermal behavior of the reversible and irreversible segments of the hysteresis loops, as predicted by the theory, is a key to the presence or absence of the “tails.” The theory, which permits arbitrary values of the quantum spin number J, generally provides a quantitative agreement with the thermal variations of both the spontaneous magnetization and the shape of the hysteresis loop.
- OSTI ID:
- 22275780
- Journal Information:
- Journal of Applied Physics, Vol. 115, Issue 3; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Magnetization changes in 2% Mn pipeline steel induced by uniaxial tensile stress cycles of increasing amplitude
Magnetic static and scaling properties of the weak random-axis magnet (Dy sub x Y sub 1 minus x )Al sub 2