Orientation-dependent low field magnetic anomalies and room-temperature spintronic material – Mn doped ZnO films by aerosol spray pyrolysis

Abstract

High quality un-doped and Mn-doped ZnO films deposited by a simple aerosol spray pyrolysis technique for 20 and 30 min were studied using electron paramagnetic resonance (EPR), X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. EPR analysis showed novel observation of low field microwave absorption (LFMA) on the manganese (Mn) doped zinc oxide (ZnO) films at various Mn concentrations. The results showed a peculiar behavior, reversal signal to that of LFMA. These findings also demonstrated that these films contain ferromagnetism at room temperature with possible applications in spintronics. Angular dependence measurements were found to induce magnetic transition from ferromagnetism to paramagnetism. Structural analysis showed that the undertaken materials are in wurtzite structures. The light absorption edge of Mn–ZnO films red shifted which enhanced the observed ferromagnetism. The direct modulation of the band gap caused by Mn–ZnO substitution is responsible for the red shift effect in absorption edge of ZnO.