2003-6
Sutdy of Metamagnetic Transition in Amorphous UPd2Al3
非晶質UPd2Al3 のメタ磁性転移の測定
The single crystal UPd2Al3 is known as a heavy Fermion compound with the elecronic specific heat coefficient g =210 mJ/mol K2, and shows an antiferromagnetic transition at TN=14 K and a superconducting transition at Tc=2.0 K. It shows a metamagnetic transition at 18 T and 4.2 K. In an amorphous UPd2Al3 prepared by a sputtering method, the antiferromagnetic and superconducting transitions disappear and a spin-glass transition is observed at 3.4 K although it has a large g =195 mJ/mol K2. A magnetization curve was measured at 4.2 K up to 27 T in the amorphous UPd2Al3. It is found that a large difference exists in the magnetization curve between the single crystal and the amorphous samples and the metamagnetic transition does not occur in the amorphous UPd2Al3.
Dept. of Phys., Tokushima University: Y. Kishimoto, Y. Kawasaki, T. Ohno
IMR, Tohoku University: Y. Homma, Y. Shiokawa, K. Koyama
Reference: T. Ohno, Y. Kishimoto, Y. Kawasaki, Y. Ushida, Y. Homma, Y. Shiokawa, T. Nishioka and M. Kontani, "Non-Fermi-liquid behavior in amorphous UPd2Al3", Physica B 329-333 (2003) 561.
単結晶UPd2Al3は転移温度TN =14 Kで反強磁性に，Tc =2.0 Kで超伝導に転移する重い電子系物質（電子比熱係数210 mJ/mol K2)として知られている．また，4.2 Kにおいてメタ磁性転移が磁場18Tで起きることが報告されている．スパッタリングにより作製した非晶質（アモルファス）UPd2Al3においては，反強磁性転移および超伝導転移はともに消失し，3.4 K でスピングラス転移する．しかし，電子比熱係数は195 mJ/mol K2と大きい．今回，非晶質UPd2Al3の27 Tまでの磁化曲線を4.2 Ｋ にて測定した．単結晶および非晶質UPd2Al3では磁化曲線に大きな相違があり，非晶質試料ではメタ磁性転移が起きないことがわかった.
徳島大学 工学部：岸本 豊，川崎 祐，大野 隆
東北大学 金属材料研究所：本間佳哉，塩川佳伸，小山佳一