Giant Non‐Saturating Exchange Striction in a Noncollinear Antiferromagnet

Magnetostriction, discovered by Joule in 1842, refers to the mechanical strain that a material undergoes in the presence of a magnetic field. Conventionally, it originates from the spin‐orbit coupling and has been predominantly explored in ferromagnets. In this work, a giant magnetostriction effect is reported in the high‐quality single crystal of a noncollinear antiferromagnet Mn3Sn. Non‐saturating magnetostriction exceeding 400 ppm is obtained, which is even larger than the saturation values of the well‐known Fe‐based giant magnetostriction ferromagnetic materials such as FeGa. Theoretical calculations reveal that the large non‐saturating magnetostriction results from a sophisticated exchange striction effect of the noncollinear antiferromagnetic spin structure, leading to a nearly linear dependence of the strain output on the applied magnetic field. This work provides an unprecedented strategy to design next‐generation magnetoelastic materials with noncollinear compensated spin structures.