Structural, optical and magnetic properties of Zn0.98Co0.02O dilute magnetic semiconductor nanoparticles

Abstract

Doped ZnO nanoparticles (NPs) are one of the most promising dilute magnetic semiconductors (DMSs). Zn0.98Co0.02O NPs were synthesized using an aqueous co-precipitation technique. XRD confirmed phase purity and the crystallite size was determined to be 20 nm using the Debye-Scherrer method. For the doped NPs, distinct surface morphology was seen in FE-SEM images. The excitonic absorption peak appeared at 371 nm in pristine ZnO NPs which blue-shifted to 363 nm on 2 % Co-doping. The doped ZnO nanocrystals exhibit considerable ferromagnetic functionality at 7 K and 300 K. The asymmetry in the hysteresis curves confirm the presence of exchange bias and spin canting in the system. The results obtained suggests that the doped NPs could be potentially useful for enhanced optoelectronics and spintronics applications.