圧力誘起超伝導物質CeIrSiの高圧下電気抵抗・比熱測定

Electrical resistivity and heat capacity measurements on the pressure induced superconductor CeIrSi

立岩 尚之   ; 芳賀 芳範   ; 松田 達磨; 池田 修悟; 山本 悦嗣  ; 奥田 悠介*; 宮内 裕一郎*; 摂待 力生*; 大貫 惇睦

Tateiwa, Naoyuki; Haga, Yoshinori; Matsuda, Tatsuma; Ikeda, Shugo; Yamamoto, Etsuji; Okuda, Yusuke*; Miyauchi, Yuichiro*; Settai, Rikio*; Onuki, Yoshichika

反転対称性のない圧力誘起超伝導物質CeIrSiについて高圧研究を行った。反強磁性状態の臨界圧力は=2.25GPaと決定された。反強磁性と超伝導状態の共存問題について議論を行う。超伝導状態はおよそ3.5GPaまで存在し、超伝導転移温度はGPaを1.6Kの最大値を示す。2.58GPaでは、超伝導転移に伴う大きな比熱異常が観測された。比熱の飛びは5.7であり、既存の超伝導物質の中で最大値を示す。CeIrSiでは強結合超伝導が実現していることが示唆される。

High pressure experiments were performed on the pressure-induced superconductor CeIrSi without inversion center. The critical pressure of the antiferromagnetic state was determined to be = 2.25 GPa. The co-existence of the antiferromagnetism and superconductivity is discussed. The superconducting region is extended up to about 3.5 GPa. The superconducting transition temperature shows a maximum value of 1.6 K around GPa. At 2.58 GPa, a large heat capacity anomaly was observed at = 1.59 K. The jump of the heat capacity in the form of is 5.7 0.1. This is the largest observed value among all superconductors studied previously, suggesting the strong-coupling superconductivity in CeIrSi.