Ferromagnetism Driven by Oxygen Vacancies in SnO<SUB>2</SUB> Nanowires

Abstract

Room temperature ferromagnetism has been observed in SnO2 nanowires synthesized by a chemical vapor deposition using Au layers as catalyst. The nanowires are homogeneous and single-crystalline grown along the [101] direction, with diameters ranging from 25 to 100 nm and length greater than 20 microm. The special magnetization reaches 0.114 emu/g for the nanowires with diameter of approximately 25 nm and reduces with increasing diameters. Branched SnO2 nanowires were prepared via a two-step vapor-liquid-solid approach, and an enhanced magnetization was obtained. To the contrary, the nanowires annealed at 1300 degrees C in air were completely transformed into the particles and exhibit weakened magnetization. These results demonstrate that the ferromagnetic properties of the samples depend on the surface-to-volume ratio of nanowires. With a combined study of photoluminescence, our results reveal that the oxygen vacancies at the surface of nanowires contribute to the ferromagnetism of SnO2 nanowires. This argument is further confirmed by a sequential annealing in a rich-oxygen atmosphere, then in a low vacuum condition.

Ferromagnetism in SnO₂ by Mechanical Milling

“…The ferromagnetic behaviors were more clearly observed in Fig.4(b) which show the hysteretic magnetization at 300 K. [6,7], are expected from these experimental results.…”

“…The ab initio calculations for the (TM) x Sn 1-x O 2 (TM= V, Mn, Fe and Co) were performed [1][2][3], and it was concluded that ferromagnetic moments appeared for Fe, Co, but not for V and Mn. In the study by our group [4], the TM oxides (V 2 O 5 , VO 2 Except for the TM-doped SnO 2 , the room temperature ferromagnetism, induced by the oxygen vacancies, has been reported for SnO 2 thin films, nano-particles and nano-wires [5][6][7][8]. As for the SnO 2 nano-particles [6], the sample preparations were performed by chemical reaction between organic solvent and metal nitrate.…”

“…XRD results showed that the particle diameter d of SnO 2 powder was 22-32 nm after MM. Magnetization measurement showed that saturated magnetization M s at 300K was 7.8×10 Except for the TM-doped SnO 2 , the room temperature ferromagnetism, induced by the oxygen vacancies, has been reported for SnO 2 thin films, nano-particles and nano-wires [5][6][7][8]. As for the SnO 2 nano-particles [6], the sample preparations were performed by chemical reaction between organic solvent and metal nitrate.…”

Improving the Catalytic Activity of Carbon‐Supported Single Atom Catalysts by Polynary Metal or Heteroatom Doping

“…[ 79 ] In addition, the atomic layer deposited process was applied to construct Pt–Ru dual‐metal dimers by successively depositing Pt and Ru atoms on N‐doped CNTs. [ 80 ]…”

Nitrogen‐doped Binary Spinel CuCo2O4/C Nanocomposite: An Efficient Electrocatalyst for Oxygen Evolution Reaction

“…Therefore, many efforts have been devoted to develop highly efficient electrocatalysts to accelerate the OER kinetics and reduce the overpotential [8] . Although IrO 2 and RuO 2 are considered as the most efficient OER catalysts with outstanding kinetics and the lowest OER overpotential, the scarcity and high cost limit their applications in large‐scale [9] . Hence, it is of great importance to explore earth‐abundant transition metal‐based OER electrocatalysts to substitute the precious metal‐based electrocatalysts.…”