Structure and room-temperature ferromagnetism evolution of Sn and Mn-doped NiO synthesized by a sol-gel process

The development of room temperature ferromagnetism is imperative for energy systems such as data storage in computers and spintronics. Herein we report a room temperature ferromagnetic study of Sn and Mn doped nickel oxide synthesized by sol gel method. The size and morphology of the samples are calculated using XRD and TEM analysis. The XRD and Fourier transform infrared (FTIR) results indicate that the synthesized NiO powders have a pure cubic structure. The variation in lattice parameters has been studied using the Rietveld refinement of X-ray diffraction pattern. The addition of dopants does not affect the structure of NiO. The presence of dopants in the doped NiO samples has been confirmed with Energy Dispersive Spectroscopy (EDS) analysis. The Photoluminescence (PL) spectrum shows enhanced luminescence intensity for Sn doped NiO than Mn doped NiO. The magnetic properties of the samples have been studied using Vibrating sample magnetometry (VSM). The pure and Mn doped NiO samples are found to exhibit ferromagnetism. The Sn doped NiO samples exhibit superparamagnetism making them suitable for applications in ferrofluids and as contrast agents for magnetic resonance imaging. The coercivity and magnetization of the Mn doped NiO samples are found to be enhanced compared to the pure NiO. The Sn doped NiO samples have very low value of coercivity compared with both pure and Mn doped NiO samples. The observed room temperature ferromagnetism in doped NiO makes it a suitable candidate for DMS devices such as MR imaging and magnetic delivery.