Sutdy of Metamagnetic Transition in Amorphous UPd2Al3
非晶質UPd2Al3 のメタ磁性転移の測定 |
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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.
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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 |