Abstract
We report the systematic study on the effect of C-doping and annealing atmosphere (air, O(2), N(2) and Ar) on the magnetic properties of pure ZnO as well as Zn(0.98)Mn(0.02)O (ZMO). We found diamagnetic behavior for pure ZnO samples in all the annealing atmospheres whereas all ZMO samples are paramagnetic except the one, which is annealed in argon. While maintaining the same annealing atmospheres and varying the C content we found that on increasing the C-doping concentration the ferromagnetic fraction in the sample increases. The observed RTFM in C-doped ZMO is possibly due to carriers introduced into the samples due to oxygen vacancies and the substitution of C at O sites. (C) 2011 Elsevier B.V. All rights reserved.