Experimental studies on magnetization in the excited state by using the magnetic field effect of light scattering based on multi-layer graphene particles suspended in organic solvents

Abstract

This article reports on experimental studies on magnetic polarization in the excited state by using magnetic field effects of light scattering (MFE_LS) together with a photoexcitation beam based on fluorinated multi-layer graphene (FG) particles suspended in an organic solvent. We observe that a magnetic field can change the light scattering of a 532 nm laser beam from the suspended FG particles, generating a MFE_LS signal with an amplitude of 60% at 900 mT. This phenomenon indicates that the suspended FG particles experience a magnetization force, leading to an orientation of the suspended FG particles in a magnetic field. We find that the magnetization force is a function of a solvent dielectric constant, an analogue phenomenon similar to magneto-electric coupling. More importantly, in the excited state the suspended FG particles exhibit more pronounced MFE_LS, as compared with the ground state, when the magnetic field effects of light scattering are combined with a photoexcitation beam of 325 nm. Clearly, the FG particles in the excited state possess a stronger magnetization relative to the ground state. This excitation-enhanced magnetization suggests an interaction between the magnetization from the localized spins and the polarization from delocalized π electrons in the FG particles. Therefore, the magnetic field effects of light scattering provide a convenient experimental method to investigate the magnetization of nanoparticles in the excited state.