New heavy-fermion compounds An4PdGa12 (An=U, Np, Pu)

✍ Scribed by R. Jardin; E. Colineau; F. Wastin; J. Rebizant; J.-P. Sanchez

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 148 KB
• Volume: 378-380
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2006.01.392

✦ Synopsis

An 4 PdGa 12 (An ¼ U, Np and Pu) are new heavy-fermion materials that crystallize in the cubic Y 4 PdGa 12 -type (Im-3 m) which is a superstructure of the AuCu 3 -type (Pm-3 m). The doubling of the cell parameters gives a ¼ 8:593(1) A ˚, a ¼ 8:579ð1Þ A ˚and a ¼ 8:611ð1Þ A for U, Np and Pu compounds, respectively. We report, for all the three compounds, noticeable enhanced value of the Sommerfeld coefficient g (up to 900 mJ mol À1 K À2 ). Magnetic measurements reveal that U 4 PdGa 12 orders antiferromagnetically at T N ¼ 43 K with an effective moment m eff ¼ 3.40(1) m B in the paramagnetic regime, in good agreement with the theoretical U 3+ free ion moment, whereas both Np and Pu homologues do not present any phase transition down 2 K.