Superconducting properties of the non-fermi-liquid system β-YbAlB4

beta-YbAlB4 is the first Yb-based heavy fermion superconductor with T-c = 80 mK. Our study using high-purity single crystals reveals that strongly type-II heavy fermion superconductivity emerges from the non-Fermi-liquid state with enhanced ferromagnetic fluctuations. High sensitivity of Tc to sample purity indicates strong pair-breaking effects due to impurities, probably of nonmagnetic type, suggesting an unconventional character of the superconductivity.