  Field-induced superconductivity is a rare phenomenon where an applied
magnetic field enhances or induces superconductivity. This fascinating effect
arises from a complex interplay between magnetism and superconductivity, and it
offers the tantalizing technological possibility of an infinite
magnetoresistance superconducting spin valve. Here, we demonstrate
field-induced superconductivity at a record-high temperature of T=9K in two
samples of the ferromagnetic superconductor
Eu(Fe$_{0.88}$Co$_{0.12}$)$_{2}$As$_{2}$. We combine tunable uniaxial stress
and applied magnetic field to shift the temperature range of the
zero-resistance state between 4K and 10K. We use x-ray diffraction and
spectroscopy measurements under stress and field to demonstrate that stress
tuning of the nematic order and field tuning of the ferromagnetism act as
independent tuning knobs of the superconductivity. Finally, DFT calculations
and analysis of the Eu dipole field reveal the electromagnetic mechanism of the
field-induced superconductivity.
