TUNNELING THROUGH RARE EARTH TRIHYDROXIDE BARRIERS.

Symmetric tunneling junctions with 4000 Angstrom thick Pb electrodes and polycrystalline insulating barriers of Lu(OH)//3, Er(OH)//3, and Ho(OH)//3 have been fabricated. The authors have observed a splitting of the tunneling characteristics of superconducting junctions containing barriers of Ho(OH)//3. The results are consistent with the existence of a bound state below the Pb gap in each of the electrodes near its interface with the magnetic layer. Depending upon the detailed nature of the bound state, this finding may have implications for the study of artificial structures containing magnetic and superconducting layers in contact.