Surface resistance and morphology of YBCO films as a function of thickness

Published

June 1, 1997

Author(s)

F. J. Stork, James A. Beall, Alexana Roshko, Donald C. DeGroot, David A. Rudman, Ronald H. Ono, Jerzy Krupka

Abstract

We have examined the thickness dependence of the growth morphology and surface resistance Rs of laser ablated YBa₂Cu₃O_7-x films with transition temperatures over 89 K and critical current densities greater than 10⁶ A/cm2 at 76 K. The thickness was varied from 50 to 1600 nm while all other deposition conditions were maintained constant. The microstructure has been characterized by scanning electron microscopy and scanning tunneling microscopy (STM). The films exhibit two-dimensional island growth at all thicknesses and the island density continuously decreased with film thickness as a power law with an exponent of -0.5. The surface resistance was measured at 76 K with a dielectric rod resonator. For films less than 300 nm thick, the fields penetrated the superconducting films, causing a rapid increase in the apparent R_s with decreasing film thickness. Films thicker than 800 nm showed microcracks and the R_s increased sharply, and no resonance was observed above 1000 nm.

Citation

IEEE Transactions on Applied Superconductivity

Volume

7

Issue

2

Pub Type

Journals

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Citation

Stork, F. , Beall, J. , Roshko, A. , DeGroot, D. , Rudman, D. , Ono, R. and Krupka, J. (1997), Surface resistance and morphology of YBCO films as a function of thickness, IEEE Transactions on Applied Superconductivity, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=27521 (Accessed May 16, 2024)