Séminaire : Temperature Dependence of Magnetic Properties of Carbon Nanotube - Based Nanocomposite with Low Content of Ferromagnetic Nanoparticles

Serghej .L. Prischepa, professeur dans le département des télecommunications à l'université biélorusse d'État de l'informatique et de radioélectronique, fera une présentation de ses travaux le mercredi 2 avril 2014 à 11h00 en salle 40 du bâtiment 40  au campus du CNRS de Cronenbourg (23 rue du Loess 67200 Strasbourg).

Équipe : MaCEPV

Titre : Temperature Dependence of Magnetic Properties of Carbon Nanotube - Based Nanocomposite with Low Content of Ferromagnetic Nanoparticles

Résumé : We investigated the magnetic hysteresis loops of CNT-based nanocomposite with very low concentration of catalytic ferromagnetic nanoparticles. Measurements were performed in a wide temperature range, from 2K up to 350K. Experimental data were analyzed within the random anisotropy model (RAM), which gives us the possibility to evaluate the micromagnetic parameters of the system. The law of the approach to saturation (LAS) revealed that, for correct description of the data the correlation function of the magnetic anisotropy axes should be taken into account. At that the obtained correlation functions depend on temperature revealing the influence of the carbon medium on the interparticle interaction. In particular, it was shown that the magnetic coherent anisotropy dominates for the low concentration of nanoparticles at low temperatures. While increasing both the nanoparticle concentration and the temperature the exchange interparticle interaction dominates diminishing essentially the coherent processes. The influence of the concentration becomes determining starting from some threshold values which leads to the dominant role of the exchange coupling in the whole temperature range.