Crystal growth and anisotropic magnetic properties of RAg2Ge2 (R=PrR=Pr, Nd and Sm) single crystals

We report the single crystal growth and anisotropic magnetic properties of the tetragonal RAg2Ge2 (R=PrR=Pr, Nd and Sm) compounds which crystallize in the ThCr2Si2 -type crystal structure with the space group I4/mmm. The single crystals of RAg2Ge2 (R=PrR=Pr, Nd and Sm) were grown by self-flux method using Ag:Ge binary alloy as flux. From the magnetic studies on single crystalline samples we have found that PrAg2Ge2 and NdAg2Ge2 order antiferromagnetically at 12 and 2 K, respectively, thus corroborating the earlier polycrystalline results. SmAg2Ge2 also orders antiferromagnetically at 9.2 K. The magnetic susceptibility and magnetization show a large anisotropy and the easy axis of magnetization for PrAg2Ge2 and NdAg2Ge2 is along the [1 0 0] direction whereas it changes to [0 0 1] direction for SmAg2Ge2. Two metamagnetic transitions were observed in NdAg2Ge2 at Hm1=1.25T and Hm2=3.56T for the field parallel to [1 0 0] direction whereas the magnetization along [0 0 1] direction was linear indicating the hard axis of magnetization.