Magnetic phase diagram and Fermi surface properties of the heavy-fermion antiferromagnet UPdCd

廣瀬 雄介; 土塔 寛*; 竹内 徹也*; 三宅 厚志*; 徳永 将史*; 仲村 愛*; 本間 佳哉*; 青木 大*; 本多 史憲*; 摂待 力生*

Hirose, Yusuke; Doto, Hiroshi*; Takeuchi, Tetsuya*; Miyake, Atsushi*; Tokunaga, Masashi*; Nakamura, Ai*; Homma, Yoshiya*; Aoki, Dai*; Honda, Fuminori*; Settai, Rikio*

The electronic state of UPdCd, which exhibits a magnetic transition at 5 K, is investigated by means of transport, high-field magnetization up to 55 T, specific heat in magnetic fields, and de Haas-van Alphen (dHvA) measurements, and compared with the non-5f compound ThPdCd. A metamagnetic transition is observed at 15-20 T, which continuously connects to in the H-T phase diagram. Although the magnetization reaches large values at high fields, the ordered magnetic moment is estimated to be small from small anomalies in specific heat at and in magnetization at . The observed dHvA frequencies reveal enhanced cyclotron effective masses of 30 , which are much heavier than those in ThPdCd. These experimental results indicate that 5f-derived bands contribute to the large electronic specific heat coefficient of 670 mJ/mol K, demonstrating the dual localized-itinerant character of 5f electrons in UPdCd.