We have studied the relation between the mechanical response and the magnetic susceptibility of

-phase Mn–Cu binary alloys, which are reentrant spin glass
RSG antiferromagnets. A close
correlation between the temperature dependency of the hysteretic magnetization due to magnetic
freezing and internal friction was observed. When the Cu concentration reached up to 30 at. %,
where the antiferromagnetic long-range order disappeared, the magnetically correlated internal
friction also disappeared. This composition effect and a remarkable vibration-amplitude dependency
of the internal friction suggested that antiferromagnetic domain walls were responsible for these
phenomena. Thus, we concluded that RSG freezing influences the dynamics of antiferromagnetic
domain walls in a similar way as that of ferromagnets, and leads to internal friction. © 2006
American Institute of Physics.