ic_B_airy¶
- Stoner.analysis.fitting.models.superconductivity.ic_B_airy(B, Ic0, B_offset, A)[source]¶
Calculate Critical Current for a round Josepshon Junction wrt to Field.
- Parameters:
B (array-like) – Magnetic Field (structly flux density in T)
Ic0 (float) – Maximum critical current
B_offset (float) – Field offset/trapped flux in coils/remanent M in junction
A (fl,oat) – Area of junction in $m^2$
- Returns:
(array) – Values of critical current
Notes
- Represents the critical current as:
- :math:`I_{c0}timesleft|frac{2 J_1left(frac{pi(B-B_{offset}) A}right)}{Phi_0}}
{frac{pi(B-B_{offset}) A}){Phi_0}}right|`
where \(J_1\) is a first order Bessel function.
For small ($<1^{-5}$)values of the Bessel function argument, this will return Ic0 to ensure correct evaluation for 0 flux.
Example
#!/usr/bin/env python3 # -*- coding: utf-8 -*- """Fit Ic(B) to Airy function.""" import os from Stoner import Data, __home__ from Stoner.analysis.fitting.models.superconductivity import Ic_B_Airy os.chdir(os.path.join(__home__, "..", "doc", "samples", "Fitting")) data = Data("data/Ic_B.txt", setas={"x": "Magnet Output", "y": "Ic"}) data.lmfit(Ic_B_Airy, result=True, header="Fit") data.setas = {"x": "Magnet Output", "y": ["Ic", "Fit"]} data.plot(fmt=["r+", "b-"]) data.annotate_fit(Ic_B_Airy, mode="eng", x=0.6, y=0.5, fontsize="small") data.title = r"Critical current vs Field for $4\mu m$ junction" data.xlabel = r"Magnetic Field $\mu_0H (\mathrm{T})$" data.ylabel = r"Critical Current $I_c (A)$"