  Spin-orbit coupling (SOC) is a key interaction in spintronics, allowing an
electrical control of spin or magnetization and, vice versa, a magnetic control
of electrical current. However, recent advances have revealed much broader
implications of SOC that is also central to the design of topological states,
including topological insulators, skyrmions, and Majorana fermions, or to
overcome the exclusion of two-dimensional ferro-magnetism expected from the
Mermin-Wagner theorem. SOC and the resulting emergent interfacial spin-orbit
fields are simply realized in junctions through structural inversion asymmetry,
while the anisotropy in magnetoresistance (MR) allows for their experimental
detection. Surprisingly, we demonstrate that an all-epitaxial
ferromagnet/MgO/metal junction with only a negligible MR anisotropy undergoes a
remarkable transformation below the superconducting transition temperature of
the metal. The superconducting junction has a three orders of magnitude higher
MR anisotropy and supports the formation of spin-triplet superconductivity,
crucial for superconducting spintronics, and topologically-protected quantum
computing. Our findings call for revisiting the role of SOC in other systems
which, even when it seems negligible in the normal state, could have a profound
influence on the superconducting response.
