Low Band Gap Co80Ni20@RGO Nanocomposite
We report a novel approach of designing ordered arrangement of disorder on the extended structures of graphene. We prepared single phase nanoparticles of Co80Ni20 alloy embedded in Reduced Graphene Oxide (RGO). Co80Ni20 shows a large moment and a soft ferromagnetic character like permalloy at room temperature. Temperature dependence of permittivity shows a behavior quite contrary to usual ceramic materials showing an increase with decreasing temperature, exhibiting a maximum. A very large magnitude of permittivity ~ 5000 is observed, which is possibly related to an interesting Maxwell-Wagner type effect arising from the charge localization in the graphene sheets. For a deeper insight of the mechanism, correlations with other phenomena are studied through magnetization, dc resistivity, I-V etc. investigations. Temperature dependent magnetization indicates toward strong ferromagnetic interaction and MH loop shows low coercivity ferromagnetic interaction at 4 K and even at room temperature.