High-quality single crystal growth of UGe and URhGe

UGe及びURhGeの高純度単結晶育成

山本 悦嗣  ; 芳賀 芳範   ; 松田 達磨; 池田 修悟; 稲田 佳彦*; 摂待 力生*; 大貫 惇睦*

Yamamoto, Etsuji; Haga, Yoshinori; Matsuda, Tatsuma; Ikeda, Shugo; Inada, Yoshihiko*; Settai, Rikio*; Onuki, Yoshichika*

強磁性超伝導体UGe及びURhGeの結晶育成条件を研究した。多結晶体はアーク溶融で、単結晶体はアーク炉内でのCzochralski法で育成を行った。アニールが結晶の質を高めるのに重要であり、試料をタンタル箔に包み石英管に真空封入する方法と固相電解エレクトロ・トランスポート法を用い、さまざまな温度でアニールを行い最適な条件を求めた。最も良好な試料として残留抵抗比で、UGeについては900、URhGeについては41のものを得ることができた。

We searched for an experimental condition of crystal growth for a ferromagnetic superconductors of UGe and URhGe. Samples were prepared for both polycrystalline and single crystals, which were arc-melted and grown by the Czochralski-pulling method in a tetra-arc furnace, respectively. Annealing is an important process to enhance sample-quality, namely the residual resistivity ratio. We tried to anneal the samples under various temperatures, which were wrapped by the Ta-foil and vacuum-sealed in the quartz ample, together with the solid state electrotransport method in ultra-high vacuum. The highest residual resistivity ratio was 900 for UGe and 41 for URhGe.