Figure 4: Magnetization measurements.
From: Room temperature organic magnets derived from sp3 functionalized graphene
(a) Temperature evolution of the mass magnetic susceptibility (χmass) of G(OH)F, measured under an external magnetic field (Hext) of 10 kOe. The insets show the hysteresis loops of G(OH)F at 5 K, which indicate non-zero coercivity and a saturation magnetization of almost 1 emu g−1. (b) Isothermal magnetization curves of G(OH)F at temperatures of 5–60 K. The insets show the profile of the hysteresis loops around the origin and the temperature dependence of coercivity (HC). (c) Isothermal magnetization curves of G(OH)F, recorded from 100 to 400 K. The inset shows the profile of the isothermal magnetization curves at 350 and 400 K, demonstrating a dramatic decrease in the curve’s gradient upon increasing temperature above 350 K; this implies a transition from an AFM state to a paramagnetic regime. (d) Temperature evolution of χmass of G(OH)F, measured under an external magnetic field of 10 kOe. The arrows show the reversibility of the χmass profile on warming the sample from 5 to 400 K and then cooling from 400 to 5 K. The inset depicts the behaviour of χmass between 300 and 400 K including its sudden drop above 370 K, which is indicative of a transition from an AFM state to the paramagnetic regime with a Néel transition temperature of about 372 K. Note: the paramagnetic signal from the non-interacting paramagnetic centres was subtracted from the χmass data.
