Different magnetic origins of (Mn, Fe)-codoped ZnO powders and thin films

The structural and magnetic properties of (Mn, Fe)-codoped ZnO powders as well as thin films were investigated. The X-ray diffraction and magnetic measurements indicated that the higher sintering temperature facilitates more Mn and Fe incorporation into ZnO. Magnetic measurements indicated that the powder sintered in air at 800 degrees C showed paramagnetic, but it exhibited obvious room temperature ferromagnetism after vacuum annealing at 600 degrees C. The results revealed that magnetic clusters were the major contributors to the observed ferromagnetism in vacuum-annealed Zn0.98Mn0.01Fe0.01O powder. Interestingly, the room temperature ferromagnetism was also observed in the Zn0.98Mn0.01Fe0.01O film deposited via pulsed laser deposition from the air-sintered paramagnetic target, but the secondary phases in the film were not detected from X-ray diffraction, transmission electron microscopy, and zero-field cooling and field cooling. Apparently, the magnetic natures of powders and films come from different origins. (C) 2012 Elsevier Ltd. All rights reserved.