Influence of Electron Doping on Magnetic Order in CeRu₂Al₁₀

Abstract

The effect of electron doping by the substitution of Rh for Ru on unconventional magnetic order in CeRu<sub>2</sub>Al<sub>10</sub> was investigated via neutron powder diffraction. In Ce(Ru<sub>1-x</sub>Rh<sub>x</sub>)<sub>2</sub>Al<sub>10</sub> with x = 0.05, 0.12, and 0.2, reorientation of the ordered moment from the c- to the a-axis takes place in all samples, while the ordering vector q=(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 μ=0.43 μ<sub>B</sub> at x=0 to μ =1.06, 1.04, and 1.02 μ<sub>B</sub> for x=0.05, 0.12 and 0.2, respectively. The continuous decrease in N´eel temperature T<sub>0</sub>(T<sub>N</sub>), despite an abrupt increase in μ , underlines the strong anisotropy in the exchange interaction in CeRu<sub>2</sub>Al<sub>10</sub>, and the fact that this anisotropy is easily suppressed by electron doping.