  DyRu2Si2 is a frustrated magnet to exhibit multiple magnetic phase transition
in zero and finite magnetic fields. We investigated and characterized the phase
transition between the partially-ordered antiferromagnetic phases at zero field
by ac susceptibility measurements. Detailed ac susceptibility measurements
reveal the novel critical dynamics of the phase transition; extremely slow
dynamics with the relaxation time in the order of 10-100 msec, speed-up of the
dynamics on cooling indicating its non-thermally activated origin and growing
of the ferromagnetic correlations towards the phase transition temperature. On
the basis of these findings, we propose the novel phase transition process,
namely, the spontaneous striped-arrangement of the precedently emergent
"belt-like" ferromagnetic spin texture.
