Defect-induced strong ferromagnetic loops in d 0 Mg and Mg+Zn doped SnO 2 nanostructures for magneto-electronic chips: magnetic impurity clusters-free

Novel diluted magnetic semiconductors are expected to revolutionize future electronic devices by integrating magnetic functionality with semiconducting properties. Herein, Mg and Zn, as non-magnetic dopants, are introduced into SnO2 to modify its electronic structure and induce robust ferromagnetic behaviour. All XRD diffraction peaks index to the tetragonal rutile SnO2 phase with no detectable impurities, while TEM shows quasi-spherical and polygonal nanoparticles. Raman spectroscopy reveals a clear variation in oxygen defect concentration among the samples, with the Mg-and-Zn codoped SnO2 exhibiting the highest level of oxygen-related defects. X-ray photoelectron spectroscopy (XPS) analysis of the codoped sample confirms that Mg and Zn are present in the +2 oxidation state, while Sn exists in the +4 state, alongside lattice oxygen vacancies indicating defect formation induced by codoping. Furthermore, the band gap energies for pristine, Mg-doped and Mg+Zn codoped SnO2 samples are 3.72, 3.88 and 3.92 eV, respectively, showing a gradual increase with modification. Room-temperature magnetic measurements using vibrating-sample magnetometry demonstrate S-shaped hysteresis loops for all samples, indicative of room-temperature ferromagnetism. A significant enhancement in saturation magnetization is observed upon doping, increasing from 0.11 emu/g (pure) to 0.57 emu/g (Mg-doped) and reaching 1.16 emu/g for the Mg+Zn codoped sample-a tenfold increase compared to pristine SnO2. These results highlight the strong effect of codoping on magnetic behaviour. As a future perspective, Mg and Zn codoping in SnO2 offers a promising route for engineering multifunctional properties in magneto-electronic devices.