Vacancy-induced interfacial ferromagnetic features in SmFeO3-filled graphitic carbon foam

Abstract

We report a novel structural and magnetic investigation of carbon foam (CFM) materials filled with SmFeO₃ crystals produced by (1) high temperature fusion between Sm₂O₃- and Fe₃C-filled carbon onions and (2) annealing of iron filled CFM with nanosized Sm₂O₃. Presence of a defect-rich monolayer-like CFM arrangement characterized by sharp interfaces with a SmFeO₃ single-crystal phase is demonstrated through TEM and HRTEM. Further, the presence of intense sp³-rich features with variable carbonate content is evidenced by XPS and Raman spectroscopy. Complementary VSM, SQUID and ESR show also presence of intrinsic magnetization features which appeared to be attributable to the interfacial vacancy-rich regions of the graphitic CFM layers, as confirmed by Raman spectroscopy. Together with these signals, possible ferromagnetic contributions from the SmFeO₃ phase and α-Fe impurities are reported. These observations highlight therefore the presence of switchable interfacial magnetization features at the carbon/SmFeO₃ interface due to the variable concentrations of vacancies at the CFM interface, opening new directions towards applications in magnetic and interfacial-driven ferroelectric devices.