A FORC investigation into the effect of Cu additive on magnetic characteristics of Co-Ni alloy nanoparticles

•Using a cost-effective polyol method, CoNi binary alloy nanoparticles were synthesized.•Effect of Cu additive on morphology, structure and magnetic properties was investigated.•The FORC analysis was employed to study the magnetic characteristics in details.•Increasing the Cu content increased the separation between soft and hard phases.•The magnetic interaction between particles was reduced when increasing the Cu content.