Oxygen-vacancy-induced room-temperature magnetization in lamellar V2O5 thin films

Abstract

In this work, we study the local atomic and electronic structures as well as oxygen-vacancy-induced magnetic properties of electrodeposited V2O5 films. Unlike stoichiometric V2O5, which is a diamagnetic lamellar semiconductor, our oxygen-defective V2O5 films are ferromagnetic at room-temperature and their saturation magnetization decreases with air exposure time. X-ray absorption spectroscopy was used to monitor the aging effect on these films, revealing that freshly-made samples exhibit only local crystalline order, whereas the aged ones undoubtedly show an enhancement of crystallinity and coordination symmetry. The mean number of oxygen atoms around V tends to increase, indicating a decrease of oxygen vacancies with time. Concurrently with the decrease of oxygen vacancies, a loss of saturation magnetization is also observed. Hence, it can be concluded that the ferromagnetism of the V2O5 films originates from a vacancy-induced mechanism, confirming the universality of this class of ferromagnetism.

Antiferromagnetism induced by oxygen vacancies in V2O5polycrystals synthesized by the Pechini method

“…This analysis suggests that the higher the vacancy density, the greater the local distortion around vanadium atoms near the oxygen vacancies. The same authors also predict a ferromagnetic state present in the system for x < ~0.13 and 0.19 < x < ~0.45, already reported in literature [31,32], and an antiferromagnetic state (0.45 ⩽ x ⩽ 0.5), which was the object of study in this work. This behavior was never observed experimentally and is going to be discussed in this paper.…”

Polaronic Correlations in Magnetic Behavior of Oxygen Deficient V2O5

“…Although V 2 O 5 is diamagnetic in nature, the experimental magnetic measurements conducted on the oxygen deficient compositions showed a large variation in the observations ranging from ferromagnetism [27,29,32], antiferromagnetism [51] to mixture of both [28,30].…”

“…Like other oxide systems, the magnetic behaviours observed are quite diverse in this case too. [27][28][29][30][31][32] Moreover, there is a also wide range of microstructure in these studies such as nanotubes, nanolamellas, nanowires and nanoparticles.…”

Synthesis and Progress of New Oxygen‐Vacant Electrode Materials for High‐Energy Rechargeable Battery Applications

“…After 48 h of drying, the film was further sintered in air and Ar for 1 h at 300 °C. Cezar et al synthetized V 2 O 5 aerogel films via electrodeposited onto boron‐doped p‐type Si (100) wafers (ρ ≥10 Ω cm, under room temperature). The electrodepositions were performed at 300 K using a stationary three‐electrode cell with a mercantile galvanostat/potentiostat.…”