Thirty years of puzzling superconductivity in Sr₂RuO₄

Superconductivity in Sr₂RuO₄ was discovered 30 years ago. Among the many intriguing aspects of this unconventional superconductor is the picture of spin-triplet superconductivity, which could potentially carry both charge and spin supercurrents. This proposal was considered for a long time but was ultimately disproven in 2019. Despite intense research over the past several years, the superconducting symmetry of the archetypal unconventional superconductor Sr₂RuO₄ remains unresolved. Here we highlight the recent controversies and give a perspective of how the final resolution may be reached.