Effect of Sn-doping on the structural, optical, dielectric and magnetic properties of ZnO nanoparticles for spintronics applications

This paper has focused on investigating the structure, dielectric, and magnetic characteristic of Sn-ZnO nanopowder with Sn (x = 0%, 2%, 4%, and 6%) synthesized by the co-precipitation technique. Our objective was to obtain the material of low dielectric constant, high electrical conductivity, and magnetism. X-ray diffraction confirmed the Sn-ZnO nanoparticles have a ZnO-like hexagonal structure. It is found that the dielectric constant, dielectric loss, and a.c conductivity of doped nanoparticles were frequency-dependent. The dielectric constant of all the doped samples were increased by the increase in the Sn-doped concentration, while the decrease in frequency increased the dielectric constant and loss. Moreover, the a.c conductivity was increased by the increase in Sn concentration and frequency. Ferromagnetism was observed in ZnO doped with 4% and 6% Sn at room temperature. In addition, a robust magnetic hysteresis loop was observed for doped with 4% Sn to ZnO nanopowder at 300 K with coercive field (H_c) ~ 49 Oe and remnant magnetization (M_r) ~ 0.189 emu/g. The loss of magnetism at higher Sn- ZnO nanopowder was assigned to the suppression of ferromagnetism through paramagnetic interactions. The experimental results showed that 4% Sn- ZnO became ferromagnetic, its lattice shrink and size decreased, which is important for excellent magnetic properties and electrical conductivity. These types of materials have a large number of applications in high-frequency devices, ultrahigh dielectric material gas sensors, spintronics, and optoelectronics.