Effect of composition in (RE)(3)Pd20Ge6 (RE=La, Ce and Nd)

An investigation of the effect of composition has been carried out for La3P d20Ge6, Ce3Pd20Ge6 and Nd3Pd20Ge6 by measuring the magnetic susceptibility specific heat and electrical resistiv ity. We have found that these compoun ds possess a very narrow homogeneity range of the Pd composition in their t ernary phase diagram and that ordering temperatures of Ce3Pd20Ge6 (a quadru polar ordering at 1.2 K and an antiferromagnetic one at 0.75 K) and Nd3Pd20 Ge6 (two antiferromagnetic ones at 0.58 and 1.85 K) are systematically redu ced by increasing the Pd concentration beyond 20, and transport properties are highly sensitive to the Pd concentration. The present results indicate that a high quality sample can he obtained at a slightly reduced Pd composi tion below 20 for both compounds and Nd compounds containing excess Pd exhi bit two additional magnetic transitions at 1.07 K and 1.40 K.