Magnetic Phase Diagram of Ce1-xGdxRu2Al10 Single Crystals

CeRu 2 Al 10 shows an unknown phase transition at T 0 ∼27 K, and GdRu 2 Al 10 shows a simple RKKY-type antiferromagnetic one at T N ∼16.5 K. In order to clarify the origin of the transition of CeRu 2 Al 10 , we have investigated the relationship between these phase transitions from the electrical resistivity, magnetization and specific heat measurements using pseudoternary Ce 1- x Gd x Ru 2 Al 10 single crystals grown by the Al self-flux method. When x increases to 0.3, T 0 decreases slightly and then disappears abruptly at x =0.4. On the other hand, T N decreases monotonically with x , and coexists with T 0 at x =0.1 and 0.3. These results indicate that the unknown phase transition of CeRu 2 Al 10 is independent of the antiferromagnetic one of GdRu 2 Al 10 , which suggests that the unknown phase transition cannot be described by only RKKY-type interaction.