Quantum measurements resolve magnetism deep inside CrSb

Researchers at the University of Cambridge and Helmholtz-Zentrum Dresden-Rossendorf have mapped the internal magnetic structure of chromium antimonide (CrSb) with detail, revealing an altermagnetic order parameter. This unconventional magnetism, where spin orientations are non-degenerate around the Fermi surface, challenges traditional classifications of magnetic materials. The work demonstrates that magnetic quantum oscillation measurements provide a high-resolution, 3D understanding of the order parameter, establishing CrSb as a prototypical metallic altermagnet; the exchange splitting between up and down spins follows the profile of a real spherical harmonic, analogous to a g-orbital of the hydrogen atom. Magnetic quantum oscillation measurements have revealed the g-wave symmetry of the altermagnetic order…