Strong magnetic anisotropy in PrRu 2 Ga 8 and PrCo 2 Al 8 single crystals.

Single crystals of LnRu 2 Ga 8 and LnCo 2 Al 8 (Ln = La and Pr) were grown using a Ga/Al self-flux method. An orthorhombic CaCo 2 Al 8 -type structure with space group Pbam (No.55) of them was identified by XRD. LaRu 2 Ga 8 and LaCo 2 Al 8 are Pauli paramagnetic down to 2 K, while PrRu 2 Ga 8 and PrCo 2 Al 8 show antiferromagnetic order at 2.5 and 5 K, respectively. Strong magnetic anisotropy in PrRu<sub>2</sub>Ga<sub>8</sub> and PrCo<sub>2</sub>Al<sub>8</sub> single crystals was found by an anisotropic magnetic measurement. The field-induced ferromagnetic state was observed in both PrRu 2 Ga 8 and PrCo 2 Al 8 for H||c. However, in the case of H⊥c, the antiferromagnetic state is robust. The strong magnetic anisotropy in PrRu 2 Ga 8 and PrCo 2 Al 8 is due to their anisotropic magnetic interactions that ferromagnetic interactions are dominant in the case of H||c while antiferromagnetic interactions for H⊥c.