In a ferromagnet/superconductor/ferromagnet (F/S/F) superconducting spin valve, the critical temperature ($T_{\mathrm{c}}$) of S is controllable by the magnetization alignment of the two F layers through pair-breaking mechanisms such as magnetic exchange fields and stray fields. In high-$T_{\mathrm{c}}$ oxide superconducting spin valves, $T_{\mathrm{c}}$-switching is more complicated than in metallic systems due to the anisotropic gap causing low-energy quasiparticle excitations down to low temperatures and, therefore, key parameters determining the origin, sign, and magnitude of $T_{\mathrm{c}}$-switching have not been fully understood yet. Here, we systematically investigate oxide superconducting spin valves with various F layers and demonstrate that the electrical resistivity of the F layers determines the sign of $T_{\mathrm{c}}$-switching. We find that insulating F layers that can suppress proximity leakage of Cooper pairs lead to magnetic-exchange-field-induced $T_{\mathrm{c}}$-switching while conducting F layers lead to $T_{\mathrm{c}}$-switching with the opposite sign. The results offer insight into the origins of the complex $T_{\mathrm{c}}$-switching effects in oxide superconducting spin valves and are useful in designing oxide superconducting spintronic devices.

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• Exchange interaction
• Proximity effect
• Spintronics
• Cuprates
• Devices for digital logic, storage & processing
• High-temperature superconductors
• Spin valves
• Resistivity measurements