Large upper critical field in non-centrosymmetric superconductor Y2C3 Original Research Article

We determine the upper critical field μ0Hc2(Tc)μ0Hc2(Tc) of non-centrosymmetric superconductor Y2C3 using two distinct methods: the bulk magnetization M (T ) and the tunnel-diode oscillator (TDO) based impedance measurements. It is found that the upper critical field reaches a value of 30 T at zero temperature which is above the weak-coupling Pauli paramagnetic limit. We argue that the observation of such a large μ0Hc2(0)μ0Hc2(0) in Y2C3 could be attributed to the admixture of spin-singlet and spin-triplet pairing states as a result of broken inversion symmetry.