Unconventional superconductivity in (TMTSF)2ClO4

We have performed detailed measurements to characterize the superconducting (Tc#~ 1.1 K) state of (TMTSF)2ClO4 using both normal and deuterated samples. Using ZF-*mSR measurements to search for spontaneous magnetic fields below Tc, we see no evidence for such fields within our resolution, thus we conclude the time reversal symmetry is likely not broken. We have also performed precession measurements in the vortex state of (TMTSF)2ClO4. The superconducting relaxation rate decreases strongly with increasing field, which may indicate a dimensional crossover in the nature of the vortex lattice. We estimate that the penetration depth is roughly 535 nm.