It has been known for a long time that electron spins can couple magnetically via the so-called Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction even if their wave functions lack any overlap. This coupling is usually collinear, i.e., the magnetic moments are pointing either in the same or opposite directions. Theoretical proposals predicted that spin-orbit scattering could also lead to a chiral indirect exchange interaction, giving rise to spiral-shaped spin structures. However, no practical realization has yet been known. In a recent research project performed jointly with colleagues from Trieste (Italy), Thuwal (Saudi Arabia), and the FZ Jülich (Germany) we discovered that MnO2 grown on the noble metal iridium are antiferromagnetically ordered along the chains but exhibit chiral magnetic oder with a 120° rotation between adjacent MnO2 chains. Density functional theory calculations confirm that this order is indeed caused by the long searched for indirect spin-orbit induced chiral echange interaction. The result has been published in Nature Communications.
