Room temperature ferromagnetism and red shift of band gap in (Mn2+, Mg2+) co-doped ZnO nanoparticles

Abstract

In this study we report, for the first time, room temperature ferromagnetism in (Zn1−xMgxMn0.01)O nanoparticles having Mg concentration in the range 0 < x < 0.10 prepared by sol–gel method. It is observed that the room temperature ferromagnetic ordering varies with Mg concentration. Compared with Mn-doped ZnO (Zn0.99Mn0.01O) nanoparticles, the (Mn, Mg) co-doped ZnO nanoparticles exhibit decreased room temperature ferromagnetism. This study also reports the balance of the two competing effects from the blue shift of band gap as a result of Mg doping and sp-d ferromagnetic exchange interaction leading to red-shift of band-gap.