Glassy magnetic behaviors in the single layered cobaltite Gd0.8Sr1.2CoO4

A comprehensive investigation of magnetic properties of single layered perovskite Gd0.8Sr1.2CoO4 has been carried out by means of dc susceptibility, ac susceptibility and magnetic relaxation. The cusp in χZFC(T) as well as a considerable frequency dependence of a shoulder in χ′(T) and a peak in χ″(T) indicates the appearance of a glassy behavior. The dynamic scaling analysis of ac susceptibility data reveals a spin glass phase below 9 K. The aging effect and long-time relaxation phenomenon are also observed in this compound. Relative to those RE2−xSrxCoO4 compounds, the large structural distortion and the stability of the lower spin state in the cobalt ions can be considered as possible reasons for the existence of only one spin glass state in Gd0.8Sr1.2CoO4.