Spin-glass behavior in ternary uranium compound U2CuGa3

The results of dc susceptibility, magnetization, magnetic relaxation and specific heat measurements on U2CuGa3, a compound reported early in the literature as exhibiting interesting magnetic properties, are presented. The temperature dependence of susceptibility measured in the zero-field cooling (ZFC) mode and in the field cooling (FC) mode displays spin-glass behavior below a characteristic temperature Tf (∼16 K) in agreement with the literature. As a new evidence for the formation of spin-glass state in this compound, the specific heat data do not show any visible singularity around Tf indicating the absence of long-range magnetic order at this temperature. Furthermore, the characteristic remanence effect and magnetic relaxation on a macroscopic time scale are also observed below Tf. The experimental results are compared with those of orthorhombic CeCu2-type spin-glass compound U2AuGa3 and hexagonal AlB2-type spin-glass compound U2PdSi3