Magnetothermal properties of iron and cobalt clusters

The magnetothermal properties of ferromagnetic transition metal clusters such as iron and cobalt containing upto 700 atoms have been computed using the superparamagnetic model. The Friedel's model of ferromagnetic clusters is also incorporated into the superparamagnetic model to produce the average magnetic moment of these clusters. The specific surface effect and the cluster size effect on the thermodynamic properties of these clusters have been carried out self-consistently using the mean field theory approximation. It has been observed that the effective magnetic moments of iron and cobalt clusters were decreased with the increase in size and temperature of the clusters. The specific heat capacity of Fe clusters for N=300 show the peak value at T=600K and that of Co clusters for N=200 exhibit the steady increase of specific heat capacity to 18 cal mol−1 K−1 at T=750K. The theoretical results computed in this work have been compared with the Stern-Gerlach experimental data and other theoretical results.