Phase formation, thermal stability and magnetic moment of cobalt nitride thin films

Cobalt nitride (Co-N) thin films prepared using a reactive magnetron sputtering process by varying the relative nitrogen gas flow (\pn) are studied in this work. As \pn~increases, Co(N), \tcn, Co$_3$N and CoN phases are formed. An incremental increase in \pn, after emergence of \tcn~phase at \pn=10\p, results in a continuous expansion in the lattice constant ($a$) of \tcn. For \pn=30\p, $a$ maximizes and becomes comparable to its theoretical value. An expansion in $a$ of \tcn, results in an enhancement of magnetic moment, to the extent that it becomes even larger than pure Co. Though such higher (than pure metal) magnetic moment for Fe$_4$N thin films have been theoretically predicted and evidenced experimentally, higher (than pure Co) magnetic moment are evidenced in this work and explained in terms of large-volume high-moment model for tetra metal nitrides.Comment: 4 pages, 4 figure

Reduction and Swelling Behaviour of Fired Iron Ore Pellets

The present project work on “Reduction and Swelling Behaviour of Fired Iron Ore Pellets” was undertaken with a view to promote the effective utilization of iron ore and coal fines in sponge iron making. Presently, India has become the world leader in sponge iron production and the production of steel by DR-EAF route is increasing day by day. In the present project work, the effect of addition of concentrated sugarcane juice binder on the physical properties of fired iron ore pellets was investigated. The crushing strength and drop number were found to be maximum at 2% binder addition, followed by a decrease with further increase in binder concentration. A reverse trend was observed in the case of porosity, i.e. porosity of fired pellets increased with rise in binder concentration from 2% to 6%. The pellets fired at 13000C were processed for reduction and swelling studies in different types of coal. The degree of reduction of fired iron ore pellets increased with increase of reduction temperature and time up to the range studied. The extent of swelling in fired iron ore pellets during their production increased with increase of reduction time, most probably due to the structural changes and fibrous growth of iron particles. SEM images of few reduced iron ore pellets were also taken

Fe and N self-diffusion in non-magnetic Fe:N

Fe and N self-diffusion in non-magnetic FeN has been studied using neutron reflectivity. The isotope labelled multilayers, FeN/57Fe:N and Fe:N/Fe:15N were prepared using magnetron sputtering. It was remarkable to observe that N diffusion was slower compared to Fe while the atomic size of Fe is larger compared to N. An attempt has been made to understand the diffusion of Fe and N in non-magnetic Fe:N