Abstract
Magnetization curves of a nanoparticle with a ferromagnetic intraparticle isotropic exchange interaction are calculated with allowance for effects of thermal deviations of atomic magnetic moments. These curves were shown to be located below magnetization curves obtained by the Néel theory of “rigid” paramagnetism that does not take into account thermal excitations of individual spins. A reductive heuristic formula that is suitable for calculating the magnetization curves of an isotropic superparamagnet in low magnetic fields is discussed. Temperatures of blocking of the total magnetic moment of an isotropic superparamagnetic nanoparticle have been estimated for the case of blocking induced by an applied magnetic field.
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Original Russian Text © E.E. Kokorina, M.V. Medvedev, 2007, published in Fizika Metallov i Metallovedenie, 2007, Vol. 103, No. 2, pp. 115–121.
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Kokorina, E.E., Medvedev, M.V. Magnetization curves of an isotropic superparamagnet and induced-blocking effect. Phys. Metals Metallogr. 103, 111–117 (2007). https://doi.org/10.1134/S0031918X07020019
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DOI: https://doi.org/10.1134/S0031918X07020019