Room temperature d0 ferromagnetism, zero dielectric loss and ac-conductivity enhancement in p-type Ag-doped SnO2 compounds

Abstract d0 ferromagnetic oxide materials have emerged as a promising material for possible application in spintronics. The recent theoretical calculation has predicted d0 ferromagnetism in Ag-doped SnO2 compounds. In this work, we have undertaken an investigation into structural, micro-structural, optical, magnetic, and electrical properties of Ag doped SnO2 compounds. Crystal structure study by the XRD pattern analysis confirms polycrystalline rutile phase with tetragonal structure. The SEM micrographs reveal the formation of uniform spherical nanoparticle morphology. The optical property study by UV/VIS spectrophotometer indicates the band-gap narrowing. A p-type conductivity was observed by Hall effect measurement and the hole concentration was found to increase with the increase in Ag doping. Ferromagnetism with Curie temperature ranging from 304 to 359 K is observed in all Ag-doped compounds, along-with a coercivity value of 240-1310 Oe, whereas un-doped SnO2 exhibited diamagnetism. The magnitude of dielectric constant and ac conductivity was observed to enhance with an increase in Ag concentration, which implies that the charge carriers' hopping is responsible for this transport. The observed ferromagnetism can be ascribed to a p–d hybridization between O and Ag ions.