Phenomenologic versus microscopic description of the nanoparticle magnetization

Abstract

We have shown that experimental data are reproduced equally well, but in this case the physical behavior can be understood in terms of the magnon gas concept. In the present work a further development of the microscopic approach has allowed us to explain another "puzzle" generated by the phenomenological description. Thus, when for samples of a decreasing size (below 10 nm) one finds values of the parameters which deviate form those of the bulk limit in an apparently chaotic pattern.