Spin filter superconducting S/I/N tunnel junctions (NbN/GdN/TiN) show a
robust and pronounced zero bias conductance peak at low temperatures, the
magnitude of which is several times the normal state conductance of the
junction. Such a conductance anomaly is representative of unconventional
superconductivity and is interpreted as a direct signature of an odd frequency
superconducting order.Comment: 5 pages, 3 figures + supplementary informatio
