Low-temperature magnetic properties of (RE)(3)Pd20Si6 (RE=La to Yb)

We have investigated the magnetic and transport properties of(RE)(3)Pd20Si6(RE=La to Yb) by measuring the magnetic susceptibility, electrical resistivity and specific heat. All rare-earth (RE) ions in these compounds are in the trivalent state and magnetically order at low temperatures except RE=La and Eu. The compounds of Nd, Sm, Gd, Tb, Dy and Ho exhibit two magnetic phase transitions. Both higher and lower ordering temperatures generally follow the de Gennes scaling. Mean-field theory for the RKKY interaction indicates a relatively small exchange constant of about 30 meV atom for these compounds. The compounds of Ce, Pr, Er, Tm and Yb show only one magnetic phase transition and deviate from the de Gennes scaling. Ce(3)Pd(2)0Si(6) is a Kondo-lattice compound with a low ordering temperature as reported earlier. The (RE)(3) Pd(2)0Si(6) compounds have a small energy splitting due to the crystalline-electric-field (CEF) effect, probably because of the large coordination number around the RE ions. The de Gennes scaling in this series of compounds is discussed as a result of the interplay between the CEF interaction and the RKKY interaction. (C) 1997 Elsevier Science S.A.