Apurva Sinha, Pranay Ranjan, Anzar Ali, Jayakumar Balakrishnan and Ajay D Thakur, "Graphene oxide and its derivatives as potential Ovchinnikov ferromagnets".
Our latest work: Graphene oxide and its derivatives as potential Ovchinnikov ferromagnets, by Apurva Sinha, Pranay Ranjan, Anzar Ali, Jayakumar Balakrishnan and Ajay D Thakur, J. Phys.: Condens. Matter 33, 375801 (2021).
Result: We demonstrated that the existence of ferromagnetism in graphene oxide and reduced graphene oxide can be ascribed to the coexistence of sp^3 and sp^2 hybridized Carbons in them. Thus, they are ideal candidates for 'Ovchinnikov ferromagnetism'.
Background: The phrase 'magnetism in Carbon nanostructures' marries two notions that do not seem to together, viz., magnetism and Carbon! Intrinsic magnetism has been the prerogative of materials containing d- and f-block elements. The Carbon allotropes are non-magnetic has been the writing on the wall. Way back in 1988, A. A. Ovchinnikov and V. N. Spector proposed the existence of Organic ferromagnets in systems they designated as intermediate graphite-diamond structures (IGDS) [Organic ferromagnets: New results, Synth. Metals 27, 615 (1988)]. The core idea to their proposal was the coexistence of both sp^3 and sp^2 hybridized Carbons in the organic material for it to demonstrate ferromagnetism. Using very high quality samples following controlled synthesis of Graphene oxide (GO) and reduced Graphene oxide (rGO), we demonstrate the evolution of ferromagnetism in these materials as the ratio of sp^3 and sp^2 Carbon is tuned.
Implications: The advantages associated with magnetic materials based on Carbon when compared to their metallic counterparts include: (a) relative ease of processing, (b) lower production costs, (c) physical and chemical stability, and (d) biocompatibility. Our demonstration paves way for controlled fabrication of Carbon based magnetic layers that may have possible applications in the domain of spintronics and other allied areas.