Tunneling into lanthanum with rare earth dopings

Conductance measurements of Al-AlOsub(x)-LaRE (RE: Pr, Tb, Ho, Gd, Y) tunnel junctions are performed in view of crystal field effects in lanthanum, doped with certain rare earth elements. The tunneling density of states of LaPr and LaHo gives support for theoretical predictions of an inelastic pair breaking mechanism. Crystal field induced structures in the tunneling density of states, also predicted, have not been detected. (orig.)