Суперпарамагнетизм нанокластеров кобальта в углеродной матрице

Abstract

Cobalt nanoclusters with an average size of 10 nm embedded in a carbon matrix were prepared by thermal treatment of carboxylated cellulose doped with cobalt cations. The cobalt nanoclustcrs exhibit a transition from ferromagnetic to superparamagnetic state with increasing temperature. The blocking temperature Tβ and the magnetic anisotropy constant K eff of the nanoclusters were estimated from the magnetic hysteresis curves as well as the temperature dependence of magnetization, being about 70 K and 5,0*10’4 J/m3 respectively. The values of these parameters agree well with these of cobalt nanoclusters obtained by commonly used methods.