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

Abstract

Abstract. The electric properties of β-vanadium bronze β-Na 0.33 V 2 O 5 have been investigated under high pressure up to 13 GPa. The metal-insulator transition accompanied by charge order is suppressed by pressure, and the superconductivity is observed around 7 GPa and 8 K (Tc). The superconducting phase adjacent to the charge ordered phase suggests an important role of charge fluctuation for the superconductivity. With further increase of pressure beyond 12 GPa, the superconductivity disappears in relevance to the appearance of a nonsuperconducting new phase.