Crystal growth and magnetic measurements on aligned single crystals of theoxides Sr3NiPtO6 and Sr3CuPtO6

Crystals of Sr3NiPtO6 and Sr3CuPtO6 were grown from a K2CO3 flux containing SrCO3, NiO or CuO, and Pt metal powder, at 1150 degrees C. The structure o f Sr3NiPtO6 was solved by means of single-crystal X-ray diffraction analysi s. The structure was refined in space group R (3) over bar c, with a = 9.58 32(1) Angstrom and c = 11.1964(1) Angstrom. Sr3CuPtO6 and Sr3NiPtO6 are str ucturally related to the parent compound, A(4)PtO(6) (A = Ca, Sr, Ba), and contain infinite chains of alternating, face-sharing PtO6 octahedra and A'O -6 (A' = Ni, Cu) trigonal prisms. Magnetic measurements were carried out on both samples using 3-5 mm long single crystals. Magnetic susceptibility st udies on oriented single crystals of Sr3NiPtO6 indicate the presence of Ni( II) ions with a large single-ion anisotropy (D = 93.7(5) K, g(parallel to) = 2.143(6), and g(perpendicular to) = 2.392(4)). In contrast, Sr3CuPtO6 exh ibits S = 1/2 Heisenberg linear chain antiferromagnetism with J/k = -24.7(1 ) K, J'/k = -7.3(8) K, g(parallel to) = 2.127(6), and g(perpendicular to) = 2.150(6).