Finn forfatter "Fjellvåg, Helmer"
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Bianchini, Federico; Fjellvåg, Helmer; Vajeeston, Ponniah (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2018)
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Bianchini, Federico; Fjellvåg, Helmer; Vajeeston, Ponniah (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2018)Transition metal containing polyanion compounds are effective excellent electrode materials for sodium-ion batteries due to their high intrinsic electrochemical potentials and to the resulting high energy density. Iron ...
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Thøgersen, Rasmus Vester; Bianchini, Federico; Fjellvåg, Helmer; Ponniah, Vajeeston (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)The rapid electrification of our society and the transition towards a larger share of intermittent renewable energy sources in our electricity grids will dramatically increase the demand for cheap energy storage. Sodium ...
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Sønsteby, Henrik Hovde; Nilsen, Ola; Fjellvåg, Helmer (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)Thin films of complex alkali oxides are frequently investigated due to the large range of electric effects that are found in this class of materials. Their piezo- and ferroelectric properties also place them as sustainable ...
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Østreng, Erik; Sønsteby, Henrik H.; Sajavaara, Timo; Nilsen, Ola; Fjellvåg, Helmer (Journal article / Tidsskriftartikkel / Published version; Peer reviewed, 2013)The ferroelectric and electro-optical properties of LiNbO3 make it an important material for current and future applications. It has also been suggested as a possible lead-free replacement for present PZT-devices. The ...
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Duparc, Marion Jeanne Louise; Sønsteby, Henrik Hovde; Nilsen, Ola; Sjåstad, Anja Olafsen; Fjellvåg, Helmer (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)Thin films of the catalytically interesting ternary and quaternary perovskites GdCoO3 and Gd0.9Ca0.1CoO3 are fabricated by atomic layer deposition using metal β-diketonates and ozone as precursors. The resulting thin films ...
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Østreng, Erik; Sønsteby, Henrik H.; Øien, Sigurd; Nilsen, Ola; Fjellvåg, Helmer (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)Thin films of sodium and potassium oxides have for the first time been deposited using atomic layer deposition. Sodium and potassium complexes of tert-butanol, trimethylsilanol and hexamethyldisilazide have been evaluated ...
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Zacharaki, Eirini; Kalyva, Maria; Fjellvåg, Helmer; Sjåstad, Anja O (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
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Bernal, Fabian Leonardo Martinez; Gonano, Bruno Raymond Gino; Lundvall, Fredrik; Wragg, David; Fjellvåg, Helmer; Veillon, Fabien; Sławińsk, Wojciech; Fjellvåg, Øystein (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)We report a synthesis method, and structural and magnetic characterization, for the fluoroperovskite NaFeF3. We have developed a wet-chemical method that allows preparation of large volumes of air-sensitive fluoroperovskites ...
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Fjellvåg, Helmer; Karen, Pavel; Kjekshus, Arne; Kofstad, Per; Norby, Truls Eivind (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 1988)© 1988 Acta Chemica Scandinavica
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Lundvall, Fredrik; Kalantzopoulos, Georgios N.; Wragg, David; Arstad, Bjørnar; Blom, Richard; Sjåstad, Anja Olafsen; Fjellvåg, Helmer (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)The sorbent enhanced water-gas shift (SEWGS) process has great potential for CO2 capture and is thereby a realistic alternative to conventional post-combustion capture by gas emission scrubbing. Nevertheless, better ...
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Sottmann, Jonas; Di Michiel, Marco; Fjellvåg, Helmer; Malavasi, Lorenzo; Margadonna, Serena; Vajeeston, Ponniah; Vaughan, Gavin B M; Wragg, David (Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)To improve lithium and sodium ion battery technology, it is imperative to understand how the properties of the different components are controlled by their chemical structures. Operando structural studies give us some of ...
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Sønsteby, Henrik Hovde; Nilsen, Ola; Fjellvåg, Helmer (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)Potassium sodium niobate (KNN) has long been considered a viable candidate for replacing lead‐based materials in piezo‐ and ferroelectric devices. The introduction of KNN on an industrial scale is highly awaited; however, ...
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Bratvold, Jon E.; Sønsteby, Henrik Hovde; Nilsen, Ola; Fjellvåg, Helmer (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)The authors here report epitaxial growth of the ferrimagnet NixFe3–xO4 (NFO) by atomic layer deposition at low temperatures. Films grow epitaxially at a reactor temperature of 250 °C and require no further postannealing ...
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Periyasamy, Manimuthu; Fjellvåg, Øystein; Fjellvåg, Helmer; Sjåstad, Anja Olafsen (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2020)Electronic phase separation is a frequent ingredient of the physics of manganites for which the colossal magnetoresistance (CMR) phenomenon is at debate. We investigate the switchable magnetoresistance (MR) effect of the ...
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Fjellvåg, Helmer; Karen, Pavel (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 1994)© 1994 Acta Chemica Scandinavica
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Fjellvåg, Helmer; Karen, Pavel; Kjekshus, Arne (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 1988)© 1988 Acta Chemica Scandinavica
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Schuler, Raphael; Norby, Truls Eivind; Fjellvåg, Helmer (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2020)We report the synthesis of phase pure Fe2WO6 and its structural characterization by high quality synchrotron X-ray powder diffraction, followed by studies of electric and thermoelectric properties as a function of temperature ...
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Kumar, Susmit; Waller, David; Fjellvåg, Helmer; Sjåstad, Anja Olafsen (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)The current study extends the insight into solid-state diffusion in alloys of the Platinum Group Metals (PGMs). Thereby, we pave the way for tailor making surface compositions of binary platinum (Pt) – rhodium (Rh) model ...
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Lundvall, Fredrik; Wragg, David; Dietzel, Pascal D.C.; Fjellvåg, Helmer (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)In the title compound, C18H18O6, the biphenyl moiety is twisted with a dihedral angle of 29.11 (10)°. The carbomethoxy groups form C-C-C-O torsion angles of -18.3 (3) and -27.7 (3)° with the attached rings, as a result ...