Percolative supercurrent in superconductor--ferromagnetic-insulator bilayers

This repository contains code and data for the paper Percolative supercurrent in superconductor--ferromagnetic-insulator bilayers.

It is structured as follows:

• exp_data contains the data collected in the measurements.
• bilayers_fittings contains the code and results for the fitting procedure of the NIS data with the Usadel model.
• network_model contains the resistive network model for zero-bias conductance and resistivity.

Experimental data

NIS data

The NIS_data folder contains the tunneling spectroscopy data of the junctions.

• The MDC004.Sample1 subfolder contains data for Sample 1 in the manuscript.

  Filename	Description
  15.dat	60x50 μm$^2$, downsweep
  16.dat	60x50 μm$^2$, upsweep
  24.dat	6x100 μm$^2$, downsweep
  25.dat	6x100 μm$^2$, upsweep
  39.dat	6x20 μm$^2$, downsweep
  40.dat	6x20 μm$^2$, upsweep
  51.dat	25x5 μm$^2$, upsweep
  68.dat	15x50 μm$^2$, upsweep
  71.dat	60x20 μm$^2$, upsweep
  77.dat	60x100 μm$^2$, upsweep
  79.dat	25x100 μm$^2$, upsweep
  81.dat	15x100 μm$^2$, upsweep
  83.dat	60x6 μm$^2$, upsweep
  91.dat	25x50 μm$^2$, upsweep
  93.dat	6x50 μm$^2$, upsweep
  95.dat	25x20 μm$^2$, upsweep
  97.dat	15x20 μm$^2$, upsweep

• The MDC004.Sample2 subfolder contains data for Sample 2 in the manuscript.

  Filename	Description
  28.dat	10x10 μm$^2$, downsweep
  29.dat	10x10 μm$^2$, upsweep
  41.dat	10x20 μm$^2$, upsweep
  45.dat	6x100 μm$^2$, upsweep
  47.dat	5x5 μm$^2$, upsweep
  49.dat	10x5 μm$^2$, upsweep
  96.dat	10x10 μm$^2$, downsweep
  97.dat	25x50 μm$^2$, upsweep
  105.dat	5x10 μm$^2$, upsweep

BAR data

The BAR_data folder contains transport data referring to the four-terminal resistance measurements of the Al bars.

Filename	Description
69.dat	Sample 2: 2, 5, 10, 20, and 50 μm, downsweep
70.dat	Sample 2: 2, 5, 10, 20, and 50 μm, upsweep
197.dat	Sample 1: 5, 10, and 20 μm, upsweep
198.dat	Sample 1: 5, 10, and 20 μm, downsweep
202.dat	Sample 1: 2 and 40 μm, upsweep
203.dat	Sample 1: 2 and 40 μm, downsweep

AFM data

The folder AFM_data contains the Atomic Force Microscopy data shown in the Supplementary Material.

EDS data

The folder EDS_data contains the energy-dispersive X-ray spectroscopy data shown in the Supplementary Material.

Bilayers fittings

The bilayers_fitting folder contains code and the output of the Usadel fittings of the NIS spectroscopy curves.

• map_fit_minimal.ipynb is the code used for the minimal fitting (used for Sample 1 in the paper).
• map_fit_complete.ipynb is the code used for the complete fitting (used for Sample 2 in the paper).
• gen_theory_data.ipynb is the code that uses the fitting results to solve the Usadel model and show the predicted NIS tunneling conductance.

Network model

The network model folder contains the code and the output of the resistive network model for the zero-bias conductance and the model for the percolative supercurrent.

• network_model.py is the code of the model.
• network_model_Sample1.ipynbis the code for Sample 1.
• network_model_Sample2.ipynbis the code for Sample 2.
• network_model_general.ipynb can be used to run the network model for zero-bias conductance with arbitrary parameters.