Dielectric and ferromagnetic properties of (Ni, Co) co-doped SnO_2 nanoparticles

摘要

Different nanoparticles (NPs) including S1, S2, S3, S4, and S5 are prepared, using the co-precipitation route. The substitution of Co and Ni into the SnO_2 matrix brought considerable modification in the physical attributes of all co-doped samples. The XRD data reveal that the calculated crystallite size is reduced from 10.54 to 1.65 nm with piling up oxygen vacancies (OVs) concentration when the Co content varies from 2.2 to 11 mM. The insertion of Co and Ni in SnO_2 (lattice) produces ample alteration in the material traits of all samples. The dielectric properties strongly exhibit doping dependence. The dielectric measures including (dielectric loss ε', dielectric loss factor tan δ, and AC conductivity σ_(ac) ) are varied with growing Co content and achieved the utmost values for S4 NPs. The tanδ shows the dispersive nature, and relaxation peaks are identified, in which intensities are enhanced with growing Co content. The dielectric behavior and σ_(ac) variations show that the dispersion is induced by polarization at the interfaces due to OVs and hopping processes. All these materials (samples) are interesting for device applications due to their large dielectric constant. The appearance of hysteresis loops show ferromagnetic nature with enhancement in saturation magnetization arises from a substantial measure of induced OVs (defects) by co-doping in the system (samples). The current work shows the doping-induced variations in dielectric and magnetic attributes. The OVs produce ferromagnetic behavior in (Ni, Co) co-doped SnO_2 NPs applicable in high-frequency dielectric devices, and spintronics.