Charge order and superconductivity in vanadium oxides

Superconductivity, charge order and magnetic transitions under high pressure in vanadium bronzes

“…We have performed the investigation of β-A 0.33 V 2 O 5 under high pressure. As the results, all A + -compounds show charge order transitions under ambient pressure and pressure-induced superconductivity [2]. A striking feature is superconducting phases competing with charge ordered phases, which suggests a significant role of charge fluctuation for the superconductivity.…”

Raman study of β‐Sr0.33V2O5 micro‐crystals under high pressure

“…The resistivity along the c-and a-axis is higher about two orders than along the b-axis. By pressure increase up to 9 GPa no sign of superconductivity was observed in all β-A 2+ 0.33 V 2 O 5 [5]. High pressure shows a strong influence on the MI phase transition temperature, which gradually decreases with increasing pressure.…”

“…The phase transition has been confirmed by magnetic susceptibility, [2], NMR, [3], and Raman measurements [4]. Electrical resistivity of this oxide was measured under high hydrostatic pressure by Yamauchi et al [5]. A metallic behavior is observed only along the b-axis (chain direction), while the resistivity behavior is semiconductive along the a-and c-axis.…”

“…High pressure shows a strong influence on the MI phase transition temperature, which gradually decreases with increasing pressure. It is estimated [5] that the critical pressure, where the charge order phase completely collapses in β-Sr 0.33 V 2 O 5 , is about 1.5 GPa. Assignment of many of the observed Raman modes as well as a fingerprint of the metal-insulator transition were found in the Raman scattering study of β-Sr 0.33 V 2 O 5 in charge disordered and charge ordered state [4].…”

7Li and51V NMR studies on local symmetry and charge disproportionation in quasi-one-dimensional conductorβ-Li0.33V2O5

“…Quasi-one-dimensional conductors β-A 0.33 V 2 O 5 (A= Li, Na and Ag) with mixed valence of V 4+ (3d 1 ) and V 5+ (3d 0 ), which undergo the metal-insulator (MI) transition accompanied by the charge ordering and show pressure-induced superconductivity, have been intensively investigated as one of the anomalous metals [2,3,4,5].…”