Room temperature magnetism of Fe doped CdS nanocrystals

Undoped and Fe doped CdS nanocrystals with Fe content of 2-5 at% of average crystallite size 1.2-2 nm have been obtained using chemical co-precipitation method with 2-mercaptoethonal as capping agent at 80 °C. X-ray diffraction (XRD) results showed that the undoped CdS nanocrystals were in mixed phase of cubic and hexagonal, where as the doped CdS nanocrystals were in hexagonal phase. Room-temperature ferromagnetism has been observed in Fe-doped CdS nanocrystals. Magnetic studies indicated diamagnetism in undoped, ferromagnetism in lightly doped (2 and 3 at%) and paramagnetism in samples of higher Fe content (4 and 5 at%). The substitutional incorporation of Fe3+ ion in Cd2+ sites was reflected in structural and electron paramagnetic resonance (EPR) measurements. Isolated as well as interacting Fe3+ ions are observed in EPR.