title: Monoclinic honeycomb-layered compound Li3Ni2SbO6: preparation, crystal structure and magnetic properties.
abstract: Two synthetic routes-ion-exchange preparation from layered Na(3)Ni(2)SbO(6) at 300 °C and direct solid-state synthesis at 1150 °C resulted in layered Li(3)Ni(2)SbO(6), a cation-ordered derivative from the rocksalt type. The Fddd form reported earlier could not be reproduced. According to the XRD Rietveld analysis, Li(3)Ni(2)SbO(6) is a pseudohexagonal monoclinic structure, C2/m, with a = 5.1828(2) Å, b = 8.9677(3) Å, c = 5.1577(2) Å, β = 109.696(2)°. No Li/Ni mixed occupancy was detected. At high temperatures, the magnetic susceptibility follows the Curie-Weiss law with a positive value of Weiss temperature, ∼8 K, indicating a predominance of ferromagnetic interactions. However, Li(3)Ni(2)SbO(6) orders antiferromagnetically at T(N)∼ 15 K. The effective magnetic moment is 4.3 μ(B)/f.u. which satisfactorily agrees with theoretical estimations assuming high-spin configuration of Ni(2+) (S = 1). Electron spin resonance (ESR) spectra show single Lorentzian shape line attributed to Ni(2+) ion in octahedral coordination. The absorption is characterized by isotropic temperature independent effective g-factor g = 2.150 ± 0.005. In accordance with the layered honeycomb crystal structure determined for Li(3)Ni(2)SbO(6), the superexchange interaction between Ni(2+) ions through Ni-O-Ni pathways within Ni(2)SbO(6) layers are assumed to be ferromagnetic, while the dominant interaction between layers is antiferromagnetic.
authors: Faculty of Physics, Moscow State University, 119991, Moscow, Russia. zvereva@mig.phys.msu.ru
authors: Elena A
authors: EA
authors: Zvereva
authors: Maria A
authors: MA
authors: Evstigneeva
authors: Vladimir B
authors: VB
authors: Nalbandyan
authors: Olga A
authors: OA
authors: Savelieva
authors: Sergey A
authors: SA
authors: Ibragimov
authors: Olga S
authors: OS
authors: Volkova
authors: Larisa I
authors: LI
authors: Medvedeva
authors: Alexander N
authors: AN
authors: Vasiliev
authors: Ruediger
authors: R
authors: Klingeler
authors: Bernd
authors: B
authors: Buechner