(108e) Magnetic Transition Changes Resulting from Strain Generated By Pressurization of Intercalated Cobalt Nanoparticles in Linked Graphene Oxide

The study of gases, liquids, and nanoparticles under high pressure and in nanoscale confinement are a promising and rapidly developing field that promises a diverse range of new research opportunities. Here, we demonstrate how a strained graphene confinement system can allow the properties of a confined species to retain properties formed at high pressure. The purpose of this study was to evaluate the effect of intercalated cobalt particles on the magnetic properties of a linked graphene oxide system. Disulfide linking was used to vary the spacing between the sheets. Cobalt nanoparticles confined between linked graphene oxide layers were pressurized between 5-25 GPa. After quenching to ambient pressure, these samples each showed different promising ferromagnetic behaviors, demonstrating that this confinement system can be used to lock in phase changes created by transient high pressure in the GPa range. Field-cooled (FC) and zero field-cooled (ZFC) magnetization measurements were performed on three samples of functionalized, reduced graphene oxide intercalated with Co nanoparticles from 5 to 25 GPa. The 0 GPa sample exhibited a paramagnetic temperature dependence with a small ferromagnetic-like anomaly at around 10K, while the 25 GPa sample showed a ferromagnetic (FM) transition ~125K along with FM transition at 10K. SQUID measurements show high-temperature 2D ferromagnets and their properties are affected by pressure applied from 0 GPa to 25 GPa at 1100°C. Different magnetic transitions are observed as we increase the pressure. These samples were characterized by Raman, XRD, HRTEM, and XPS.