Evidence for superconductivity and a pseudogap in the new magnetic compound PrAg6In6

Abstract

Direct evidence for superconductivity in the new magnetic compound PrAg 6 In 6 is revealed for the first time. The distinct Andreev-reflection current is observed in metallic point contacts (PC) based on this compound. The data obtained provide reason enough to suggest that the rise of superconductivity strongly depends on the local magnetic order varying over the sample volume. The triangular-shaped PC spectra (dV/dI V ( )) in the vicinity of the zero-bias voltage suggest an unconventional type of superconducting pairing. As follows from the temperature and magnetic field dependences of the PC spectra, the superconducting energy gap structure transforms into the pseudogap one as the temperature or the magnetic field increases. PACS: 74.70. Ad, 74.80.Fp According to the conventional views, only a perfect antiferromagnetic (AFM) order is well compatible with superconductivity in a quite broad temperature range. New magnetic superconductors whose magnetic structures are far from having perfect AFM order provide a new insight into the problem of interplay between magnetism and superconductivity. A few years ago, a new class of magnetic superconductors with the ThMn 12 -type crystal structure was perceived to exist. Radio-frequency impedance and heat capacity measurements carried out on several compounds of this family have revealed distinct features in the corresponding characteristics which might be associated with superconductivity in some regions of the samples. Such indications of superconductivity were found in