Ferromagnetic ordering and weak spin-glass-like effect inPr2CuSi3 and Nd2CuSi3

Abstract

We present the results of the temperature dependences of ac and dc susceptibilities,high-field magnetization, magnetic relaxation, specific heat, and electrical resistivity ofPr2CuSi3 and Nd2CuSi3, compounds previously shown in the literature to exhibit interesting properties. It is observed thatthe investigated compounds undergo a ferromagnetic phase transition at a characteristic temperatureTC (= 9.8 K forPr2CuSi3 and5.6 K for Nd2CuSi3), where zero-field-cooled dc susceptibility shows a rapid increase followed by a sharp peak just belowTC.Below TC, the magnetization curve displays an open hysteresis loop and a steep rise at low fields, whileirreversible magnetism and long-time magnetic relaxation effects can be observed. Furthermore, nearTC both the real and imaginary components of the ac susceptibility show a large peak with asmall frequency shift of the peak position, and a sharp anomaly appears in thespecific heat and electrical resistivity curves. These unusual features observed forPr2CuSi3 and Nd2CuSi3 strongly suggest the formation of huge ferromagnetic clusters accompanied by a very weakspin-glass-like effect in both samples. The obtained results are discussed by comparingthem with the data reported for other 2:1:3 intermetallic compounds and some alloyedcompounds with different stoichiometry.