Intrinsic magnetism in Fe doped SnO2 nanoparticles

Iron doped semiconducting nanoparticles Sn1−xFexO2 with x=0, 0.001, 0.002, 0.003, 0.004, 0.01 and 0.03 were prepared by a sol–gel method. The X-ray diffraction, Transmission Electron Microscopy measurements confirm the rutile structure with no impurity phase. The three characteristic lines of electron spin resonance (ESR) are observed in the doped samples for all compositions, which is a clear evidence for rhombic Fe3+ in rutile phase. The line width of ESR increases with increase in Fe concentration due to induced disorder. The spin-pumping effect is observed at temperatures below 250 K for the samples with x=0.01 and 0.03. However, based on the Curie–Weiss susceptibility, iron is in paramagnetic state and is subject to weak antiferromagnetic interaction. Blue shift in the optical band gap is observed with increase in the Fe content.

The ESR spectra reveal that the nature of Fe in Sn1−xFexO2 samples is isolated rhombic Fe3+-ion in rutile phase and the Fe content (x=0.01 and 0.03), an extra spin-pumping is observed below 250 K.Figure optionsDownload as PowerPoint slideResearch Highlights
► The g-values of the ESR spectra reveal that the isolated rhombic Fe3+ ion in rutile phase.
► The line width of ESR increases with increase in the Fe3+-content due to the ion induced disorder effect.
► The magnetization confirms that the Fe3+-ions have weak antiferromagnetic interactions.