Effect of aluminum doping concentration on optical, magnetic and microstructural properties of MnZnO thin films

Al doped MnZnO thin films have been successfully deposited via the gel route by varying concentration of Al between 1 and 3%. Identification of the chemical components of the films was done using Fourier Transform Infrared Spectroscopy (FTIR). The structural properties evaluated by using X-ray diffraction showed that the Al doped MnZnO films are amorphous and only film with 3% Al doping exhibits hexagonal wurtzite structure along a-axis orientation. The surface morphological studies from Scanning Electron Microscope (SEM) showed the nano-crystalline grains on the surface. Transmission among the wavelength range 300-900 nm was found to be decreased with increase of doping percentage of Al. The optical band gap was decreased from 3.46 to 3.4 eV when% of Al doping was increased till 2.5%. Further increase in Al percentage to 3% increased band gap. The hysteresis curves showed ferromagnetic behavior and magnetic properties were enhanced with increase in Al%.