ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The introduction of a temperature dependence to the effective penetration depth as calculated in the strong-coupling limit of the coupled grain model is discussed. Assuming a phenomenological Gorter–Casimir behavior for the intrinsic penetration depth of YBa2Cu3O7−δ (YBCO) and a simple model for the temperature-dependent intergrain critical current density, the coupled grain model is found to predict a kinetic inductance which accurately fits the relative phase velocity, vφ(T)/vφ(T0), measured on coplanar YBCO transmission lines. This indicates that the coupled grain model provides an adequate physical interpretation of the empirical penetration depth proposed by, e.g., Rauch et al. [J. Appl. Phys. 73, 1866 (1993)] and suggests that the kinetic inductance is strongly influenced by boundaries between grains with minor relative misalignment. The average grain size and critical current density of the grain boundaries were estimated at a=140–240 nm and Jgc(0)=3.5×1010–1×1011 A m−2, respectively. We argue that the coupled grain model may prove suitable for implementation in microwave circuit design software, as thin film preparation techniques mature in the sense of providing samples with highly reproducible properties.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.356656
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