Dynamic Cantilever Magnetometry of Paramagnetism with Slow Relaxation

Abstract

Dynamic cantilever magnetometry is a sensitive method that has been widely used in studying magnetic anisotropy in ferromagnetic materials and Fermi surface in quantum materials. We study a cobalt-iridium metal-metalloligand coordination polymer using dynamic cantilever magnetometry. The experimental data of dynamic cantilever magnetometry are well explained using the proposed model for Langevin paramagnetism with slow relaxation. Based on the proposed model, we calculate the magnetization and magnetic susceptibility of paramagnetic materials from frequency shifts of a cantilever. The extracted magnetization and magnetic susceptibility are consistent with those obtained from conventional DC and AC magnetometry. The proposed slow relaxation picture is probably a general model for explaining dynamic cantilever magnetometry data of paramagnetic materials, including previously observed dynamic cantilever magnetometry data of paramagnetic metals [Gysin et al. 2011 Nanotechnology 22 285715].