Signatures of Filamentary Superconductivity up to 94 K in Tungsten Oxide WO2.90
- Resource Type
- Authors
- Alexander Shengelaya; K. Conder; K. A. Müller
- Source
- Journal of Superconductivity and Novel Magnetism. 33:301-306
- Subject
- 010302 applied physics
Superconductivity
Materials science
Condensed matter physics
Transition temperature
chemistry.chemical_element
Tungsten
Condensed Matter Physics
01 natural sciences
Electronic, Optical and Magnetic Materials
law.invention
Magnetization
chemistry
Electrical resistivity and conductivity
law
Condensed Matter::Superconductivity
Phase (matter)
0103 physical sciences
Cuprate
010306 general physics
Electron paramagnetic resonance
- Language
- ISSN
- 1557-1947
1557-1939
We report results of the search for possible superconducting state in tungsten oxides WO3−x with various oxygen deficiency 0 < x < 1. In samples with one particular composition WO2.9, the signatures of superconductivity with the same transition temperature Tc = 80 K were registered by means of magnetization measurements. By lithium intercalation, the Tc was further increased to 94 K. The observed small superconducting fraction and the absence of clear transition in resistivity measurements indicate that the superconductivity is localized in small regions which do not percolate. Electron Paramagnetic Resonance experiments showed the presence of W5+ − W5+ electron bipolarons in reduced tungsten oxide samples. It is proposed that such bipolarons form and cluster within crystallographic shear planes which exist in the Magneli phase of WO2.9 (W20O58) and represent charge-carrier rich quasi-1D stripes or puddles. When decreasing temperature, superconducting state can be established locally in such regions similar to cuprates. The obtained results demonstrate that the Magneli-type tungsten oxides are promising materials to explore high-temperature superconductivity above liquid nitrogen temperature.