Giant magneto-elastic coupling in a metallic helical metamagnet

摘要

Using high resolution neutron diffraction and capacitance dilatometry we showthat the thermal evolution of the helimagnetic state in CoMnSi is accompaniedby a change in inter-atomic distances of up to 2%, the largest ever found in ametallic magnet. Our results and the picture of competing exchange and stronglyanisotropic thermal expansion that we use to understand them sheds light on anew mechanism for large magnetoelastic effects that does not require largespin-orbit coupling.