Large upper critical field in non-centrosymmetric superconductor Y2C3

We determine the upper critical field mu H-0(c2)(T-c) 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 Tat zero temperature which is above the weak-coupling Pauli paramagnetic limit. We argue that the observation of such a large mu H-0(c2)(0) in Y2C3 could be attributed to the admixture of spin-singlet and spin-triplet pairing states as a result of broken inversion symmetry. (C) 2010 Elsevier Ltd. All rights reserved.