Defect induced room-temperature ferromagnetism and enhanced dielectric property in nanocrystalline ZnO co-doped with Tb and Co

Microstructural, magnetic and dielectric properties of hydrothermally prepared dual ions doped (Tb and Co) zinc oxide (Tb0.05Co0.05Zn0.90O) nanoparticles are investigated in the present work. The polycrystalline single phase of undoped and doped ZnO nanoparticles with hexagonal wurtzite structure is confirmed by X-ray diffraction pattern. Raman and Photoluminescence spectroscopy studies are recorded at room temperature and the measurements ruled out the presence of any impurity phase in both undoped and Tb, Co co-doped ZnO samples. Also, the Photoluminescence emission spectra for the entire samples confirm the presence of various defect centers inside co-doped ZnO wurtzite nanostructure. Magnetic and dielectric properties of co-doped ZnO system are enhanced remarkably as compared to undoped as well as some mono-doped ZnO systems. The room temperature ferromagnetism with high coercive field and magnetization has been observed in the magnetic measurement and the outcome of the measurement will be fruitful for future spintronics device applications. The dielectric behavior has been explained on the basis of Maxwell-Wagner-Sillars polarization phenomenon. High value of dielectric constant was observed due to the presence of grain boundary defects and various others defect centers at the surface of the hexagonal rod like doped ZnO nanostructures.