Magnetic, optical and phase transformation properties of Fe and Co doped VO2(A) nanobelts

In this work, the effects of Fe and Co dopants on the optical bandgap and structural, morphological, and magnetic properties of VO2(A) nanobelts with rectangular cross-sections were studied. The optimized hydrothermal method with proper parameters was used to synthesize the samples. The XRD analyses show that the hydrothermal method promotes the formation of VO2(B) rather than the usual VO2(A) and causes the tetragonal-monoclinic transformation in VO2. Furthermore, expanding the VO2 lattice constant by dopants reveals that Fe3+ and Co2+ are successfully substituted into the lattice sites of V4+. Also, obtained results indicate the optical band gap increment with dopants and superparamagnetic behavior of the samples at room temperature.