A two-nanometer crystal stretch uncovers magnetism long hidden in ruthenium dioxide

An ultrathin, strained ruthenium dioxide (RuO₂) film showed signs of hidden magnetic order.

Researchers combined spin-resolved photoemission with X-ray and optical tests to detect a spin texture consistent with magnetism.

The findings help settle earlier disagreement over whether RuO₂ is magnetic.

They also suggest strain can engineer RuO₂’s magnetism, boosting interest in altermagnets and spintronic devices.