Effect of Isovalent Doping on the Magnetic Properties of ZnMnO Diluted Magnetic Semiconductors

The magnetic properties of a ZnMnO diluted magnetic semiconductor isovalently doped with Mg and S have been successfully studied. ZnMnO alloys were prepared with different concentrations of magnesium and sulfur by using ultrasonic spray pyrolysis technique; additionally, the films were doped for free charge carriers by using nitrogen. For ZnMnO doped with 5% of Mg, the Curie temperature reached 104 K, and second-phase magnetic precipitates were observed with increasing Mg concentration. On the other hand, the sulfur doped ZnMnO showed an increased Curie temperature higher than room temperature due to increased number of holes which mediated the magnetic exchange interaction between magnetic ions.