Origin of room temperature d0 ferromagnetism and characteristic photoluminescence in pristine SnO2 nanowires: A correlation

Arrays of SnO2 nanowires are fabricated by employing a wet chemical template assisted sol–gel route using ordered nanoporous anodic aluminium oxide as the host. The origin of room temperature d0 ferromagnetism in pristine polycrystalline SnO2 nanowires is investigated by correlating photoluminescence and electron paramagnetic resonance (EPR) studies. It has been found that the naturally grown structural defects of oxygen vacancies namely singly ionised oxygen vacancy (VOradical dot) clusters induce the characteristic photoluminescence and contribute in ferromagnetism of pristine SnO2 nanowires at room temperature. The presence of the VOradical dot structural defects in the pure SnO2 nanowires is also assured by the EPR spectroscopy. Present study will help understand the puzzle about the unexpected magnetic phenomenon in these undoped wide band gap oxide semiconductors.