Single crystal growth of plutonium compounds

プルトニウム化合物の単結晶育成と物性

芳賀 芳範   ; 青木 大*; 大貫 惇睦*

Haga, Yoshinori; Aoki, Dai*; Onuki, Yoshichika*

「高温」超伝導体PuCoGaやPuRhGaの発見以来、プルトニウムを初めとする超ウラン化合物に関心が集まっている。本講演では日本で始まったばかりのプルトニウム化合物の磁性と超伝導研究の現状についてレビューする。

The discovery of the high-temperature superconductivity in PuCoGa and PuRhGa accelerated research activity in trans-uranium compounds. We report recent progress in Japan of sample preparation and physical property measurements on plutonium compounds. Single crystals of plutonium compounds such as superconducting PuRhGa, antiferromagnetic PuGa and paramagnetic PuIn were successfully grown by the self-flux method and encapsulated for the measurements at Ar-circulated glove boxes in the Oarai research establishment, Japan Atomic Energy Agency. Physical properties measurements were performed at the Oarai branch, IMR, Tohoku University, which is located close to the sample preparation facility. To avoid the self-heating effect due to the strong radiation, a specially designed encapsulation was used to keep good thermal contact between the sample and the cryostat. Using those crystals, anisotropy in the superconducting state was revealed for PuRhGa. In PuIn, we succeeded in observing de Haas-van Alphen effect for the first time and revealed 5-itinerant electronic states.