Type-I/Type-II superconductivity in noncentrosymmetric compound Ir${}_2$Ga${}_9$

Abstract

We have performed magnetization, specific heat, and muon spin relaxation ($\mu$SR) measurements on single crystals of the noncentrosymmetric superconductor Ir${}_2$Ga${}_9$. The isothermal magnetization measurements show that there is a crossover from Type-I to Type-II superconductivity with decreasing temperature. Potential multi-band superconductivity of Ir${}_2$Ga${}_9$~is observed in the specific heat data. $\mu$SR~measurement is performed to map the phase diagram of Ir${}_2$Ga${}_9$, and both Type-I and Type-II superconductivity characteristics are obtained. Most importantly, a more unique region with the coexistence of Type-I and Type-II $\mu$SR signals is observed. In addition, time reversal symmetry is found to be preserved in Ir${}_2$Ga${}_9$ by zero field $\mu$SR measurement.