A streamlit app that extracts the Critical current (Ic) from a given data set of I and V

We first find dV/dI from the given rows of V and I, we then find the Savgol filter (Savitzky-Golay filter) of 1s order for the dV/dI (d^2V / d^2I). Savgol filter gives us a smooth 2nd order differential.

Corresponding to the negative and positive Ic, the 2nd order derivative will show spikes (as in fig), The I for which this peaks out is taken for both negative and positive current and then averaged out.

The following are the default parameters in this process

The length of the filter window = 11

The order of the polynomial used to fit the samples. polyorder must be less than window_length = 3

sigNoiseThresh = 3

cutoff = 15 # cut off ends of dVdI which result in spurious maxima