Spin-glass behavior in U₂PtSi₃

We present the DC magnetization, specific heat and magnetic relaxation measurements on well-annealed polycrystalline sample of U₂PtSi₃. All the main characteristics of spin-glass behavior are observed. They are: (1) frozen-in magnetic moments below a freezing temperature T_f and, hence, a peak in the field-dependent magnetization; (2) absence of visible singularity in temperature dependence of specific heat at T_f; (3) irreversibility in magnetization below T_f; (4) remanent magnetic relaxation on macroscopic time scales after changing the magnetic field below T_f. The spin-glass state in U₂PtSi₃ at low temperatures is considered to originate from the randomly frustrated U-U interactions resulting from the disordering of Pt and Si atoms on the crystallographic sites.