Aging in a topological spin glass

We have examined the nonconventianal spin-glass phase of the two-dimensiona l kagome antiferromagnet (H3O)Fe-3(SO4)(2)(OH)(6) by means of ac and de mag netic measurements. The frequency dependence of the ac susceptibility peak is characteristic of a critical slowing down at T(g)similar or equal to 18 K. At fixed temperature below T-g, aging effects are found which obey the s ame scaling law as in spin glasses or polymers. However, in clear contrast with conventional spin glasses, aging is remarkably insensitive to temperat ure changes. This particular type of dynamics is discussed in relation with theoretical predictions for highly frustrated nondisordered systems.