Superconductivity of 2.2 K under Pressure in Helimagnet CrAs

Abstract

We report resistivity measurements of the helimagnet CrAs under pressures. The helimagnetic transition with T_N ∼ 265 K at ambient pressure is completely suppressed above a critical pressure of P_c ∼ 0.7 GPa, and superconductivity is observed at ∼2.2 K for zero resistance, which exists in a wide pressure range extending beyond 3 GPa. Both the upper critical field H_c2 and the coefficient A in the resistivity increase toward P_c, suggesting that the superconductivity of CrAs is mediated by electronic correlations enhanced in the vicinity of the helimagnetic phase.