Low-Temperature Magnetic Orderings and Fermi Surface Properties of LaCd₁₁, CeCd₁₁, and PrCd₁₁with a Caged Crystal Structure

We succeeded in growing single crystals of cage-structure compounds RCd 11 (R: La, Ce, and Pr) and precisely studied their low-temperature magnetic and electronic properties by measuring electrical resistivity, magnetic susceptibility, magnetization, specific heat, and the de Haas–van Alphen (dHvA) effect. We found antiferromagnetic ordering at 0.44 and 0.39 K in CeCd 11 and PrCd 11 , respectively, and clarified the magnetic phase diagrams of the compounds. In addition, low-lying crystalline electric field (CEF) schemes were proposed from the specific heat results of both compounds. From the present study, the antiferromagnetic ordering in PrCd 11 is found to be of the exchange-induced type with a singlet ground state. From the dHvA experiment, we detected small dHvA branches ranging from 7×10 5 to 2×10 7 Oe, which correspond to small Fermi surfaces. This is mainly due to a small Brillouin zone based on a large unit cell. Moreover, the dHvA frequencies and cyclotron masses are approximately the same among RCd 11 , revealing a localized character of 4 f electrons in CeCd 11 and PrCd 11 .