Reduced room-temperature ferromagnetism in intermediate conducting regime of V doped ZnO

摘要

The mechanism of room temperature (RT) ferromagnetism for low doping concentration of 2.5% V in ZnO have been systematically discussed by measuring structural, electrical, and magnetic properties. The evolution of the Curie temperature from above RT in insulated V:ZnO powders to 270 K in semiconducting samples was observed with increasing carrier concentration by using different hydrogenated annealing treatment. The results provide a direct observation that the free carriers suppress the ferromagnetism and might be associated the phenomena of charge-transfer and interaction between bound magnetic polarons.