Extended short-range ferromagnetic order with cluster-glass behavior in Dy₂AuSi₃

We present the results of ac and dc susceptibilities, high-field magnetization, magnetic relaxation and electrical resistivity measurements for a ternary intermetallic compound Dy₂AuSi₃ with a hexagonal phase dominant crystal structure derived from the AlB₂-type. Both the ac and dc susceptibilities show a field and frequency dependent peak around T_C ∼ 12.5 K, while evident irreversible magnetism and long-time magnetic relaxation behavior can be observed below T_C. These metastable magnetic properties suggest that an extended short-range ferromagnetic order occurs near T_C, i.e. the formation of ferromagnetic cluster state. This is further confirmed by the magnetization and electrical resistivity measurements and by a dynamic analysis of the ac susceptibility data. According to the extended short-range ferromagnetic order model, ferromagnetic clusters in Dy₂AuSi₃ could exist with larger geometric dimensions, interact magnetically with each other and result in the observed cluster-glass behavior at low temperatures.