We have studied the superconducting properties of ultra-thin YBa2Cu3O7 layers using trilayers of YBa2Cu3O7 sandwiched between semiconducting (PrxY1-x)Ba2Cu3O7 layers. We find that superconducting parameters such as the transition temperature Tc, the upper critical field Hc2(0), and the Pippard coherence length ξ0 deviate from bulk values when the YBa2Cu3O7 layer is thinner than four unit cells. The dependence of Tc on the thickness of YBa2Cu3O7 with different Pr composition x of the (PrxY1-x)Ba2Cu3O7 adjacent layers shows a similar behavior, even though Tc depends strongly on x. We observed a linear temperature dependence of Hc2(T) from 1 to 100 unit-cell thick YBCO layers. The plot of the Pippard coherence length ξ0 versus 1/Tc(R/Rn = 0.1) of 1-8 unit-cell YBCO shows a linear relationship suggesting no appreciable change in Fermi velocity.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering