Influence of electron doping on magnetic order in CeRuAl

CeRuAlの磁気秩序における電子ドープ効果

小林 理気*; 金子 耕士   ; 斉藤 耕太郎*; Mignot, J.-M.*; Andr, G.*; Robert, J.*; 脇本 秀一  ; 松田 雅昌*; Chi, S.*; 芳賀 芳範   ; 松田 達磨*; 山本 悦嗣  ; 西岡 孝*; 松村 政博*; 谷田 博司*; 世良 正文*

Kobayashi, Riki*; Kaneko, Koji; Saito, Kotaro*; Mignot, J.-M.*; Andr, G.*; Robert, J.*; Wakimoto, Shuichi; Matsuda, Masaaki*; Chi, S.*; Haga, Yoshinori; Matsuda, Tatsuma*; Yamamoto, Etsuji; Nishioka, Takashi*; Matsumura, Masahiro*; Tanida, Hiroshi*; Sera, Masafumi*

The effect of electron doping by the substitution of Rh for Ru on unconventional magnetic order in CeRuAl was investigated via neutron powder diffraction. In Ce(RuRh)Al with = 0.05, 0.12, 0.2, reorientation of the ordered moment from the - to the -axis takes place in all samples, while the ordering vector = (0 1 0) remains unchanged within this concentration range. The moment reorientation is accompanied by an enhancement in its size by a factor of 2.4, from =0.43 at = 0 to =1.06, 1.04, and 1.02 for = 0.05, 0.12 and 0.2, respectively. The continuous decrease in Nel temperature (), despite an abrupt increase in , underlines the strong anisotropy in the exchange interaction in CeRuAl, and the fact that this anisotropy is easily suppressed by electron doping.