We report supercurrent transport measurements in hybrid Josephson junctions comprising semiconducting InAs nanowires with epitaxial ferromagnetic insulator EuS and superconducting Al coatings. The wires display a hysteretic superconducting window close to the coercivity, away from zero external magnetic field. Using a multi-interferometer setup, we measure the current-phase relation of multiple magnetic junctions and find an abrupt switch between $\pi$ and 0 phases within the superconducting window. We attribute the $0\text{−}\pi$ transition to the discrete flipping of the EuS domains and provide a qualitative theory showing that a sizable exchange field can polarize the junction and lead to the supercurrent reversal. Both 0 and $\pi$ phases can be realized at zero external field by demagnetizing the wire.

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• Coherence length
• Critical current
• Electrical conductivity
• Exchange interaction
• Ferromagnetism
• Josephson effect
• Magnetic domains
• Magnetization switching
• Proximity effect
• Quantum transport
• Superconducting phase transition
• Superconductivity