Change in Unusual Magnetic Properties by Rh Substitution in CeRu2Al10

We have studied the Rh substitution (electron doping) effect in the Kondo semiconductor CeRu 2 Al 10 , which orders antiferromagnetically below ($T_{0}=27$ K), by specific heat $C$, magnetic susceptibility $\chi$, electrical resistivity $\rho$, and Hall resistivity $\rho_{\text{H}}$ measurements of Ce(Ru 1-x Rh x ) 2 Al 10 ($x=0.12$, 0.2, 0.23, 0.34) single crystals. $T_{0}$ decreases monotonically with an increase in $x$. In addition, new anomalies occur at $T_{1}\sim 6.5$ and $T_{2}\sim 3.0$ K in all the Rh substitution samples. However, $T_{1}$ and $T_{2}$ are almost independent of $x$. The shape of the anomaly at $T_{0}$ in $\chi(T)$ changes with Rh substitution, which implies the reorientation of the ordered moment. These phenomena indicate that the magnetic properties of CeRu 2 Al 10 are strongly associated with the number of $4d$ electrons.