In a superconductor, the coherence length is the mean distance between two electrons in a Cooper pair. How is the coherence length experimentally measured?

# [Physics] How is the superconducting coherence length measured experimentally

condensed-mattersuperconductivity

## Best Answer

From Ginzburg-Landau theory we have

$\mu_0 H_{c2} = \frac{\hbar}{2 e \zeta(0)^2} \frac{T_C-T}{T_c} $

where $\mu_0 = 4 \pi \times 10^{-7} H/m$, $H_{c2}$ is the upper critical field of the sample, $\hbar$ is Dirac's constant and $T_c$ is the critical temperature. You can measure $H_{c2}$ as a function of temperature and fit your data to the above equation to find the coherence length $\zeta(0)$.

Ref. : J.F. Annett, Superconductivity, Superfluidity and Condensates, Oxford UP,2004