Improved Coercivity of Solvothermally Grown Hematite (α-Fe_2O_3) and Hematite/Graphene Oxide Nanocomposites (α-Fe_2O_3/GO) at Low Temperature

摘要

α-Fe2O3 and α-Fe_2O_3/graphene oxide (GO) nanocomposites are synthesized by solvothermal method in acetonitrile medium at 200 ℃. XRD studies reveals the formation of α-Fe_2O_3 and α-Fe_2O_3/GO nanocomposites. Raman studies indicate that GO in α-Fe_2O_3/GO system was more disordered than GO. The enhanced low temperature magnetic saturation and coercivity in α-Fe_2O_3 and α-Fe_2O_3/GO are related to frozen canted spins. Blocking temperature of α-Fe_2O_3/GO is 348 K, which also shows higher coercivity of the order of about 3064 Oe at 5 K. The α-Fe_2O_3/GO composite exhibits thermal hysteresis at Morin transition (ΔT_M=11 K).