Room temperature ferromagnetism of Si-doped ZnO thin films prepared by sol-gel method

Pure ZnO and Si-doped ZnO thin films were deposited on quartz substrate by using sol-gel spin coating process. X-ray diffraction analysis shows that all the thin films have hexagonal wurtzite structure and preferred c-axis orientation. Si-doped ZnO films show room temperature ferromagnetism （RTFM） and reach the maximum saturation magnetization value of 1.54 kA.m at 3 % Si concentration. RTFM of Si-doped ZnO decreases with the increasing annealing temperature because of the formation of SiO2. Photoluminescence measurements suggest that the RTFM in Si-doped ZnO can be attributed to the defect complex related to zinc vacancies Vzn and oxygen interstitials O1.

Room temperature ferromagnetism of boron-doped ZnO nanoparticles prepared by solvothermal method

In this study, B-doped ZnO nanoparticles were synthesized by template-free solvothermal method. X-ray diffraction analysis reveals that B-doped ZnO nanoparti- cles have hexagonal wurtzite structure. Field emission scanning electron microscopy observations show that the nanoparticles have a diameter of 50 nm. The room tem- perature ferromagnetism increases monotonically with increasing B concentration to the ZnO nanoparticles and reaches the maximum value of saturation magnetization 0.0178 A.ma.kg-1 for 5 % B-doped ZnO nanoparticles. Moreover, photoluminescence spectra reveal that B doping causes to produce Zn vacancies （Vzn）. Magnetic moment of oxygen atoms nearest to the B-Vzn vacancy pairs can be considered as a source of ferromagnetism for B-doped ZnO nanoparticles.