Magnetic properties and substitution effect of Pr for Ce3Al11

We report the electrical resistivity, magnetization and ac magnetic susceptibility of orthorhombic La3Al11-type Ce3-xPrxAl11. Ce3Al11 and Pr3Al11 with two inequivalent rare earth sites (RI on the 2a, RII on the 4g) show successive phase transitions. Through our experiments, CeI orders ferromagnetically at 6.2 K and incommensurate antiferromagnetically at 3.1 K along the b-axis, and CeII orders antiferromagnetically at 3.2 K along the a-axis. Furthermore, we found that there is a relation between the magnetic transitions of Ce3Al11 and those of Pr3Al11 and Kondo effect for Ce survives even in a magnetic host Pr3Al11. We suggest that RI and RII site have strong anisotropy along the b- and a-axis, respectively.