Crystal Growth, Structure, and Physical Properties of Ln2MGa12 (Ln = La, Ce; M = Ni, Cu)

Single crystals of Ln 2 M Ga 12 ( Ln = La, Ce; M = Ni, Cu) have been synthesized using Ga flux and their structures determined by single-crystal X-ray diffraction. The Ln 2 M Ga 12 ( Ln = La, Ce; M = Ni, Cu), which is isostructural to Ce 2 PdGa 12, crystallizes in the tetragonal P 4/ nbm (No. 125, origin choice 2) space group, with Z = 2 and lattice parameters a ≈ 6.1 Å and c ≈ 15.3 Å. Ce 2 NiGa 12 orders antiferromagnetically at 10 K and specific heat measurements suggest it is a moderate heavy-fermion system with γ ≈ 191 mJ mol −1 K −2 . Magnetic susceptibility data show paramagnetic behavior down to 2 K for Ce 2 CuGa 12, whereas specific heat data suggest a magnetic transition below 1.8 K, with a moderately enhanced γ-value of 69 mJ mol −1 K −2 . Metallic behavior is observed below 300 K for each compound. A large positive and nonsaturating magnetoresistance up to 216% at a field (μ 0 H) of 9 T is also observed for La 2 NiGa 12 . We present the crystal structures and physical properties of the Ln 2 M Ga 12 ( Ln = La, Ce; M = Ni, Cu) series.