c-axis tunneling and magnetic field splitting of the quasiparticle states in planar ndba2Cu3O7−δ/prba2cu3O7−δ/ndba2cu3O7−δ quasi-homostructures

Abstract

We report on high quality planar junctions fabricated from well characterized c-axis quasi-homoepitaxial NdBa₂ Cu₃O_7−δ/PrBa₂Cu₃O_7−δ/NdBa₂Cu₃O_7−δ multilayers. C-axis tunneling spectroscopy investigations provide evidence of quasiparticle tunneling that is commonly observed for superconductor-insulator-superconductor (SIS) junctions. We observed a temperature dependent BCS like gap giving 2Δ/K_BT_c=6. The tunneling conductance dI/dV of the junctions in parallel magnetic field reveals an anomalous splitting of the superconducting quasiparticle density of states. The magnitude of the splitting can be related to the magnetic moment of the quasiparticles.