Pure and transition metal dopednano-crystalline Sn1-xTMxO2 (x = 0.0, 0.05, TM = Ni, Co and Mn)were synthesized in aqueous solution by chemical Co-precipitation technique. X- ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM), electron diffraction,UV – visible absorption spectroscopy and room temperature magnetization measurements were performed to investigate the structural and microstructural, morphology, optical and magnetic properties of pure and doped samples. The structure calculations revealed that Co and Ni atoms have been incorporatedin the SnO2hostlattice.For Mn, the XRD analysis detected that SnO phase was formed instead during the synthesis process.HRTEM and XRD studies indicated that the particle size is in the range of quantum dot size except for Mn. For optical measurement, the quantum confinement effect was suggested to be the dominant reason for the great increase of the optical bandgap with respect to the bulk material. Magnetization measurements revealed that all doped samples were ferromagnetic in nature. Well defined strong hysteresis loop was detected for Co doped SnO2 nanoparticles. It was suggested that the ferromagnetism is intrinsic in origin.It is not due to ferromagnetic metal clusters nor due to the presence of additional ferromagnetic phases. The strong ferromagnetic signal especially for Co doped SnO2makes it a candidate for spintronic applications.
The Primary Origin of Excellent Dielectric Properties of (Co, Nb) Co-Doped TiO2 Ceramics: Electron-Pinned Defect Dipoles vs. Internal Barrier Layer Capacitor Effect