Epitaxial Zn0.9Mn0.1O thin films ablated from targets synthesized by wet chemistry method

Zn0.9Mn0.1O thin films were prepared by pulsed laser deposition (PLD) on c-Al2O3(0 0 0 1) substrates. The polymeric precursor method was used to synthesize the powders from which the ablation targets were fabricated. Zn0.9Mn0.1O films ablated from these targets showed excellent epitaxial growth with a full-width at half-maximum (FWHM) ∼0.07°. Probably, the purity offered by the soft chemistry methods to prepare ceramic-type polycrystalline compounds with nanometric particle size plays an important role in achieving high-quality films of novel oxides as Mn-doped ZnO. Interestingly, the Zn0.9Mn0.1O films displayed well-defined magnetic hysteresis loops both at room temperature and 5 K, which points out to the presence of ferromagnetic order in the films. Nevertheless, the mechanism leading to room temperature ferromagnetism in the Mn-doped ZnO is not fully established. Probably, unpaired electron spins responsible for ferromagnetism in the films have their origin in the oxygen vacancies, especially on the surfaces of the oxide nanoparticles. The oxygen deficiency would result from thin film growth conditions as the studied samples were grown in low-pressure oxygen atmosphere (1×10−4 mbar).