Metamagnetism of PrCu2X2 (X=Si and Ge)

Magnetization processes have been studied on PrCu2X2 (X=Si and Ge) single crystals with TN=19.5 and 14.4 K, respectively. The isothermal magnetization for X=Si along the easy axis H//c at 2 K shows a reversible single-step metamagnetic transition. The magnetization curve for X=Ge and H//c is irreversible; the virgin ascending process shows a four-step metamagnetic transition, while the magnetization in the descending process decreases to a value smaller than that of the virgin curve through a single-step transition. The possible origins for the irreversible transition are discussed