Materials (Nov 2021)

Effects of Non-Stoichiometry on the Ground State of the Frustrated System Li<sub>0.8</sub>Ni<sub>0.6</sub>Sb<sub>0.4</sub>O<sub>2</sub>

  • Evgeniya Vavilova,
  • Timur Salikhov,
  • Margarita Iakovleva,
  • Tatyana Vasilchikova,
  • Elena Zvereva,
  • Igor Shukaev,
  • Vladimir Nalbandyan,
  • Alexander Vasiliev

DOI
https://doi.org/10.3390/ma14226785
Journal volume & issue
Vol. 14, no. 22
p. 6785

Abstract

Read online

The non-stoichiometric system Li0.8Ni0.6Sb0.4O2 is a Li-deficient derivative of the zigzag honeycomb antiferromagnet Li3Ni2SbO6. Structural and magnetic properties of Li0.8Ni0.6Sb0.4O2 were studied by means of X-ray diffraction, magnetic susceptibility, specific heat, and nuclear magnetic resonance measurements. Powder X-ray diffraction data shows the formation of a new phase, which is Sb-enriched and Li-deficient with respect to the structurally honeycomb-ordered Li3Ni2SbO6. This structural modification manifests in a drastic change of the magnetic properties in comparison to the stoichiometric partner. Bulk static (dc) magnetic susceptibility measurements show an overall antiferromagnetic interaction (Θ = −4 K) between Ni2+ spins (S = 1), while dynamic (ac) susceptibility reveals a transition into a spin glass state at a freezing temperature TSG ~ 8 K. These results were supported by the absence of the λ-anomaly in the specific heat Cp(T) down to 2 K. Moreover, combination of the bulk static susceptibility, heat capacity and 7Li NMR studies indicates a complicated temperature transformation of the magnetic system. We observe a development of a cluster spin glass, where the Ising-like Ni2+ magnetic moments demonstrate a 2D correlated slow short-range dynamics already at 12 K, whereas the formation of 3D short range static ordered clusters occurs far below the spin-glass freezing temperature at T ~ 4 K as it can be seen from the 7Li NMR spectrum.

Keywords