Structural and Magnetic Characteristics of Polyol Synthesized Cobalt Nanoparticles with Ruthenium and Samarium Additives: A First-Order Reversal Curve Analysis

Abstract

As a 3d metal element, cobalt (Co) has been widely utilized in the synthesis of magnetic materials, inducing high magnetic anisotropy and Curie temperature. Here, a polyol method is used to synthesize Co nanoparticles (NPs) with Ru and Sm rare-earth element additives. X-ray diffraction patterns indicate the formation of different crystal structures of Co NPs with the additives, whereas field-emission scanning electron microscopic images show similar mean diameters and size distributions of the NPs with spherical-like morphology. Hysteresis loop measurements show higher coercivity (H_c= 315 Oe) and lower saturation magnetization (M_s= 84.59 emu/g) of Ru-added Co NPs compared to Sm-added Co NPs (H_c= 66 Oe and M_s= 109.94 emu/g). First-order reversal curve analysis manifests predominant single domain and superparamagnetic contributions for Ru- and Sm-added Co NPs, respectively, thereby shedding light on their different magnetic behavior at room temperature.