Original Paper(Vol.61 No.5 pp.399-401)

Observation of Superconductivity at Very High Pressure and Low Temperature -Pressure-Induced High Temperature Superconductivity of Calcium-

Katsuya SHIMIZU

Abstract:We have developed a combined extreme condition of very low-temperature down to 50 mK and ultrahigh pressure up to 200 GPa; using a 3He/4He dilution refrigerator and a diamond-anvil cell (DAC). Producing techniques for ultrahigh pressure and measuring techniques for electrical resistance are developed especially for studying the pressure-induced superconductivity of simple systems such as element. For example, the pressure-induced superconductivity of calcium is reviewed which is the highest superconducting temperature in the elements.

Key Words:Superconductivity, High pressure, Low temperature, Insulator-metal transition, element