# Superconductor: What form of paramters (like London penetration depth) to use?

I am dealing with thin film and LN2 temperature, and am trying to calculate values such as the Pearl Length, but am trying to find clarification as to which value of $\lambda_L$ to use in this case. e.g.

$\lambda_L(t,T)$ with T = 0 or T = 77K?

I have other formula, such as the kinetic inductance for a CPW, but the articles I am pulling them from are somewhat unclear which forms of the parameters they are using. Any help is appreciated.

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CPW = Co-Planar Waveguide? –  Qmechanic Apr 22 '13 at 7:37