Sánchez-Marín, N.N.Sánchez-MarínCuchillo, A.A.CuchilloKnobel, M.M.KnobelVargas, P.P.Vargas2026-10-192026-10-192018-04Sánchez-Marín, N.; Cuchillo, A.; Knobel, M.; Vargas, P. (2018-04). A phenomenological approach to study the effect of uniaxial anisotropy on the magnetization of ferromagnetic nanoparticles. JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 452, 230-242. https://doi.org/10.1016/j.jmmm.2017.12.0770304-88531873-4766https://hdl.handle.net/20.500.12740/25467We study the effect of the uniaxial anisotropy in a system of ideal, noninteracting ferromagnetic nanoparticles by means of a thermodynamical model. We show that the effect of the anisotropy can be easily assimilated in a temperature shift T*(a), in analogy to what was proposed by Allia et al. (2001) in the case of interacting nanomagnets. The phenomenological anisotropic T*(a) parameter can be negative, indicating an antiferromagnetic-like behavior, or positive, indicating a ferromagnetic-like character as seen in the inverse susceptibility behavior as a function of temperature. The study is done considering an easy axis distribution to take into account the anisotropy axis dispersion in real samples (texture). In the case of a volumetric uniform distribution of anisotropy axes, the net effect makes T*(a) to vanish, and the magnetic susceptibility behaves like a conventional superparamagnetic system, whereas in the others a finite value is obtained for T*(a). When magnetic moment distribution is considered, the effect is to enhance the T*(a) parameter, when the dispersion of the magnetic moments becomes wider. (C) 2017 Elsevier B.V. All rights reserved.enMagnetic AnisotropyFerromagnetic NanoparticlesMagnetic SusceptibilityLangevin functionArticulohttps://doi.org/10.1016/j.jmmm.2017.12.077