Influence of electron doping on magnetic order in CeRuAl

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.