Sn addition effect on magnetic reversibility of Co-Ni alloy nanoparticles based on the FORC results

Ternary Co-Ni-Sn nanoparticles were prepared using a chemical polyol method, and their magnetic and structural properties were investigated by a vibrating sample magnetometer (VSM), first-order reversal curve (FORC), X-ray diffraction and scanning electron microscopy (SEM). It was found that, by increasing the amount of Sn, the magnetization of the synthesized samples decreased from 65 to 34 emu/g. In addition, the XRD patterns of low Sn concentration samples showed the presence of both CoNi and Sn structures along with a trace of cobalt oxide. However, the crystallinity of the resulting samples decreased to an amorphous state. According to the results of FORC analysis, the soft and hard magnetic phases were completely separated and the percentage of reversibility was reduced due to the increased Sn concentration, so that the percentages of the reversibility and irreversibility were equal in the samples with the highest concentration of Sn. From SEM images, the change in the amount of constituents leads to a morphological variation from spherical-shaped to sheet-like particles.