Precessional effects in the linear dynamic susceptibility of uniaxial superparamagnets: Dependence of the ac response on the dissipation parameter
نویسندگان
چکیده
A single domain ferromagnetic particle is characterized by an internal potential, having several local states of equilibrium with potential barriers between them. If the particles are small ~; 10 nm! so that the potential barriers are relatively low, the magnetization vector M may cross over the barriers due to thermal agitation. The ensuing thermal instability of the magnetization results in the phenomenon of superparamagnetism. This problem is important in information storage, rock magnetism, and the magnetization reversal observed in isolated ferromagnetic nanoparticles. The dynamics of the magnetization M of a superparamagnetic particle is usually described by the Landau-Lifshitz or Gilbert ~LLG! equation
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