Using a multitarget high oxygen pressure sputtering system, we have produced in six high quality epitaxial YBa2Cu3O7-x/PrBa2Cu3O7-x/YBa2Cu3O7-x trilayer structures on SrTiO3 (001) substrates with PrBa2Cu3O7-x barrier thicknesses ranging from 10 to 30 nm. The structural properties were determined by x-ray diffraction. Rutherford Back Scattering (RES) and Transmission Electron Microscopy (TEM) analysis, which showed an epitaxial growth of the trilayers with sharp and clean interfaces. I-V and dl/dV vs V measurements showed a clear SIS quasiparticle tunneling behavior with well developed peaks at +/- 45 mV indicating the presence of energy gap structures at +/-2 Delta and flat background conductances at high bias. Ratios of the conductance at zero bias, G(0), to the normal conductance at 150 mV, G(150), of about 10 % are observed. These characteristics can be related to the very good interfaces and superconducting properties observed in our heterostructures.
Epitaxial growth and tunneling properties of YBa2Cu3O7-x/PrBa2Cu3O7-x/YBa2Cu3O7-x trilayer structures
BOBBA, Fabrizio;NIGRO, Angela;CUCOLO, Anna Maria
1997
Abstract
Using a multitarget high oxygen pressure sputtering system, we have produced in six high quality epitaxial YBa2Cu3O7-x/PrBa2Cu3O7-x/YBa2Cu3O7-x trilayer structures on SrTiO3 (001) substrates with PrBa2Cu3O7-x barrier thicknesses ranging from 10 to 30 nm. The structural properties were determined by x-ray diffraction. Rutherford Back Scattering (RES) and Transmission Electron Microscopy (TEM) analysis, which showed an epitaxial growth of the trilayers with sharp and clean interfaces. I-V and dl/dV vs V measurements showed a clear SIS quasiparticle tunneling behavior with well developed peaks at +/- 45 mV indicating the presence of energy gap structures at +/-2 Delta and flat background conductances at high bias. Ratios of the conductance at zero bias, G(0), to the normal conductance at 150 mV, G(150), of about 10 % are observed. These characteristics can be related to the very good interfaces and superconducting properties observed in our heterostructures.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
