Evidence for the formation of the spin-glass state inU2PdSi3

Abstract

Results of dc magnetization, magnetic relaxation, specific heat, and electrical resistivity measurements on a well-annealed polycrystalline ${\mathrm{U}}_{2}{\mathrm{PdSi}}_{3}$ sample are reported. The temperature dependence of the dc magnetization exhibits a cusp at a characteristic temperature ${T}_{f}$ that strongly depends on the applied magnetic field. Below ${T}_{f},$ the magnetic relaxation measurements reveal a decay of the isothermal remanent magnetization vs time that is drastically slower than above ${T}_{f}.$ No anomalies around ${T}_{f}$ are observed in the specific heat and electrical resistivity data, which rules out the existence of usual long-range spatial magnetic order. These results can be considered as clear evidence for the formation of a spin-glass state in ${\mathrm{U}}_{2}{\mathrm{PdSi}}_{3}$ with a freezing temperature ${T}_{f}=13.5\mathrm{K}.$ The necessary randomness in the U-U magnetic exchange interactions arises from a statistical distribution of Pd and Si atoms on a crystallographic site of the ${\mathrm{U}}_{2}{\mathrm{PdSi}}_{3}$ crystal lattice.