Naturally formed ultrathin V2O5 heteroepitaxial layer on VO2/sapphire(001) film

Littlejohn, Aaron J.; Yang, Yunbo; Lu, Zonghuan; Shin, Eunsung; Pan, KuanChang; Subramanyam, Guru; Vasilyev, Vladimir; Leedy, Kevin D.; Quach, T.; Lu, Toh‐Ming; Wang, G.-C.

doi:10.1016/j.apsusc.2017.05.009

Cited by 17 publications

(15 citation statements)

References 38 publications

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“…Argon gas was selected as carrier gas during the reduction process of pentavalent vanadium oxides at 600 °C in the reaction furnace. Annealing conditions (e.g., temperature and gas pressure) are of vital importance to the compositions and lattice structure of vanadium oxides . The varied oxygen partial pressures (

P_{O_{2}}

) were used to explore the formation and the lattice of VO 2 nanostructure thin films .…”

Section: Resultsmentioning

confidence: 99%

“…Annealing conditions (e.g., temperature and gas pressure) are of vital importance to the compositions and lattice structure of vanadium oxides. [20] The varied oxygen partial pressures (P O 2 ) were used to explore the formation and the lattice of VO 2 nanostructure thin films. [21,22] Here, we annealed the as-prepared thin films by varying the gas pressure from 7.4 to 1.9 Torr.…”

Section: Doi: 101002/pssb201900785mentioning

confidence: 99%

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Strained VO₂ Nanostructure Thin Films with an Unaffected Insulator–Metal Transition

Huang

Wang

Wei

et al. 2020

Physica Status Solidi (b)

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Insulator–metal transition (IMT) brings some fantastic physical changes and accompanies structure phase transition (SPT) in correlated vanadium dioxide (VO2) materials. It is still in dispute whether the electron–phonon interaction induced by the lattice deformation or the electron–electron correlation drives the IMT transition. An alternative and challenging way to understand the mechanism is to separate SPT from IMT in VO2. Understanding and manipulating strain and defect in VO2 is important to regulate the IMT behavior. Herein, strained VO2 nanostructure thin films with unaffected IMT behavior are presented. The shifted phonon modes and the decreased interplanar spacing indicate the presence of the in‐plane strain in VO2 nanostructure thin films. Such structural strains do not affect the transition temperature but provide a platform for the light modulation. It is believed that the unaffected IMT is beneficial for in‐depth understanding of the IMT and SPT behaviors in VO2 and even the creation of advanced electronic devices.

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P_{O_{2}}

) were used to explore the formation and the lattice of VO 2 nanostructure thin films .…”

Section: Resultsmentioning

confidence: 99%

Section: Doi: 101002/pssb201900785mentioning

confidence: 99%

Strained VO₂ Nanostructure Thin Films with an Unaffected Insulator–Metal Transition

Huang

Wang

Wei

et al. 2020

Physica Status Solidi (b)

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“…Microwave-assisted heating has also been used to produce nanostructured VO 2 via solvothermal synthesis [41,42]. Radio frequency (RF) sputtering [43], metal-organic chemical vapor deposition (MOCVD) [44], and PLD [32] methodologies have also been implemented to achieve nanometer-thick films. However, there are still many opportunities for the development of thin film and nanocrystalline microwave-assisted VO 2 syntheses to decrease the overall cost.…”

Section: Applications and Contemporary Synthesis Methodsmentioning

confidence: 99%

Accelerated microwave-assisted synthesis and in situ X-ray scattering of tungsten-substituted vanadium dioxide (V1−xWxO2)

Wilson

Gibson

Argo

et al. 2021

Journal of Materials Research

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Vanadium dioxide (VO 2 ) has been widely studied due to its metal-insulator phase transition at 68°C, below which it is a semiconducting monoclinic phase, P2 1 /c, and above it is a metallic tetragonal phase, P4 2 /mnm. Substituting vanadium with transition metals allows transition temperature tunability. An accelerated microwave-assisted synthesis for VO 2 and 5d tungsten-substituted VO 2 presented herein decreased synthesis time by three orders of magnitude while maintaining phase purity, particle size, and transition character. Tungsten substitution amount was determined using inductively coupled plasma-optical emission spectroscopy. Differential scanning calorimetry, superconducting quantum interference device measurements, and in situ heating and cooling experiments monitored through synchrotron X-ray diffraction (XRD) confirmed the transition temperature decreased with increased tungsten substitution. Scanning electron microscopy analyzed through the line-intercept method produced an average particle size of 3-5 μm. Average structure and local structure phase purity was determined through the Rietveld analysis of synchrotron XRD and the least-squares refinement of pair distribution function data.

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“…Different peak positions can be attributed to the different phases of VOx. [38][39][40][41][42][43][44] The Raman peaks at ~ 275 cm -1 and ~520 cm -1 can be assigned to the A1g vibration modes of the high temperature metallic phase of a V2O3 thin film, while the peak at ~330 cm -1 is the phonon mode of Eg. 38 The broad peak at 443 cm -1 is related to magnon scattering in the anti-ferromagnetic phase of V2O3 thin film.…”

Section: Microstructure Of the Vox Coatingsmentioning

confidence: 99%

“…39 The peaks located at ~ 138 cm -1 , 700 cm -1 , and ~1020 cm -1 agree with the accepted peak position for a V2O5 film. [40][41][42] For the VO2 films, the Raman vibrational modes are commonly located at ~158 cm -1 , 275 cm -1 , 445 cm -1 and ~520 cm -1 . 43, 44 Based on previous publications and the coating parameters used in this work, it is reasonable to conclude that the VOx films coated on glass substrates consisted of various phases of vanadium oxide.…”

Section: Microstructure Of the Vox Coatingsmentioning

confidence: 99%

Vanadium oxide coatings to self-regulate current sharing in high-temperature superconducting cables and magnets

Yang

Martínez

Muley

et al. 2020

Journal of Applied Physics

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High-temperature superconductors such as REBa2Cu3O7-δ (REBCO, RE = rare earth) enable high-current cables and high-field magnets. By removing the turn-to-turn insulation in a magnet application, recent experiments demonstrated that REBCO magnets can self-protect against catastrophic damage during a superconducting-tonormal transition (quench), i.e. when the stored magnetic energy rapidly converts to heat. The current can bypass the hot spot during a quench, thereby reducing the localized heat dissipation. The removal of the insulation between turns, however, leads to excessive eddy currents during current ramping, thereby forcing a muchprolonged magnet charging time. To address this issue, we investigate vanadium oxide (VOx) coatings as a temperature-dependent self-switching medium that automatically manages current sharing. VOx coatings (with 1.70 ≤ x ≤ to 2.07) were deposited by reactive cathodic arc deposition, initially on insulating glass to determine the electrical properties, and later on commercial REBCO tapes. The coatings are Xray amorphous but with short-range crystalline ordering according to Raman spectrometry. The resistivity of VOx decreased by at least three orders of magnitude when the temperature increased from 80 to 300 K. The coating process is compatible with commercial REBCO tapes as evidenced by the negligible change of the critical current caused by the coating process. The results from current sharing experiments and circuit analysis suggest that the VOx coating can effectively self-regulate current sharing in REBCO magnets, suppress excessive eddy currents and enable selfprotection during quenches.

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Naturally formed ultrathin V2O5 heteroepitaxial layer on VO2/sapphire(001) film

Cited by 17 publications

References 38 publications

Strained VO₂ Nanostructure Thin Films with an Unaffected Insulator–Metal Transition

Strained VO₂ Nanostructure Thin Films with an Unaffected Insulator–Metal Transition

Accelerated microwave-assisted synthesis and in situ X-ray scattering of tungsten-substituted vanadium dioxide (V1−xWxO2)

Vanadium oxide coatings to self-regulate current sharing in high-temperature superconducting cables and magnets

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Naturally formed ultrathin V2O5 heteroepitaxial layer on VO2/sapphire(001) film

Cited by 17 publications

References 38 publications

Strained VO2 Nanostructure Thin Films with an Unaffected Insulator–Metal Transition

Strained VO2 Nanostructure Thin Films with an Unaffected Insulator–Metal Transition

Accelerated microwave-assisted synthesis and in situ X-ray scattering of tungsten-substituted vanadium dioxide (V1−xWxO2)

Vanadium oxide coatings to self-regulate current sharing in high-temperature superconducting cables and magnets

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Resources

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Strained VO₂ Nanostructure Thin Films with an Unaffected Insulator–Metal Transition

Strained VO₂ Nanostructure Thin Films with an Unaffected Insulator–Metal Transition