Structural, optical and magnetic properties of (ZnO)_(1-x)(MnO_2)_x thin films deposited at room temperature

摘要

The structural, magnetic and optical properties of (ZnO)_(1-x)(MnO_2)_x (with x = 0.03 and 0.05) thin films deposited by pulsed laser deposition (PLD) were studied. The pellets used as target, sintered at different temperatures ranging from 500 ℃ to 900 ℃, were prepared by conventional solid state method using ZnO and MnO_2 powders. The observation of non-monotonic shift in peak position of most preferred (101) ZnO diffraction plane in XRD spectra of pellets confirmed the substitution of Mn ions in ZnO lattice of the sintered targets. The as-deposited thin film samples are found to be polycrystalline with the preferred orientation mostly along (110) diffraction plane. The UV-vis spectroscopy of the thin films revealed that the energy band gap exhibit blue shift with increasing Mn content which could be attributed to Burstein-Moss shift caused by Mn doping of the ZnO. The deposited thin films exhibit room temperature ferromagnetism having effective magnetic moment per Mn atom in the range of 0.9-1.4μ_B for both compositions.