Room temperature ferromagnetism and cooling effect in dilute Co-doped ZnS nanoparticles with zinc blende structure

Room temperature ferromagnetism in the dilute (1 at.%) Co-doped ZnS with zinc blende structure synthesized from the aqueous solution is observed. Its structure and magnetic properties are investigated. The value of saturation magnetization for the sample prepared at rapid cooling condition is larger than that of natural cooling. First-principle calculations prove that the antiferromagnetic coupling state of Co-S-Co and the ferromagnetic coupling state of Co-S-Zn-S-Co are stable; and the formation energy of Co-S-Co is lower than that of Co-S-Zn-S-Co. The ferromagnetic coupling state of Co-S-Zn-S-Co is formed by the p-d hybridization interaction and RKKY interaction.