Metamagnetic behaviors in RRu₂Al₁₀(R = Tb, Dy, Ho) single crystals

We measured the magnetization M and the specific heat C of TbRu₂Al₁₀, DyRu₂Al₁₀ and HoRu₂Al₁₀ single crystals. We observed antiferromagnetic transitions at the temperature T = 15 K for TbRu₂Al₁₀, 6.5 and 5.1 K for DyRu₂Al₁₀ and 5.0 K for HoRu₂Al₁₀ in the temperature dependences of M divided by the applied magnetic field, M/H. The magnetization curves exhibit metamagnetic behaviors below their magnetic transitions of all materials. M of TbRu₂Al₁₀ at T = 2 K along the c-axis shows the metamagnetic behavior at H = 1.2, 1.6 and 3.2 T and shows a complex behavior with small jumps around H = 4, 5 and 6.2 T along the a-axis. As for DyRu₂Al₁₀, the metamgnetic behaviors were observed at H = 0.16, 1.35 and 1.8 T along the c-axis. In addition to the magnetic transitions at T = 5.1 and 6.5 K, we observed an unusual drop around 2 K in the temperature dependence of M/H and correspondingly a kink in the magnetic specific heat at T = 1.5 K. As for the specific heat of HoRu₂Al₁₀, an upturn due to a nuclear contribution in the specific heat was observed below 1.5 K