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>
The non-stoichiometric system Li<sub>0.8</sub>Ni<sub>0.6</sub>Sb<sub>0.4</sub>O<sub>2</sub> is a Li-deficient derivative of the zigzag honeycomb antiferromagnet Li<sub>3</sub>Ni<sub>2</sub>SbO<sub>6</sub>. Structural...
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| Autores principales: | , , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/ddab78965ce7453e8723fbd2fa956373 |
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| Sumario: | The non-stoichiometric system Li<sub>0.8</sub>Ni<sub>0.6</sub>Sb<sub>0.4</sub>O<sub>2</sub> is a Li-deficient derivative of the zigzag honeycomb antiferromagnet Li<sub>3</sub>Ni<sub>2</sub>SbO<sub>6</sub>. Structural and magnetic properties of Li<sub>0.8</sub>Ni<sub>0.6</sub>Sb<sub>0.4</sub>O<sub>2</sub> 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 Li<sub>3</sub>Ni<sub>2</sub>SbO<sub>6</sub>. 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 (<i>Θ</i> = −4 K) between Ni<sup>2+</sup> spins (<i>S</i> = 1), while dynamic (ac) susceptibility reveals a transition into a spin glass state at a freezing temperature <i>T</i><sub>SG</sub> ~ 8 K. These results were supported by the absence of the λ-anomaly in the specific heat <i>C</i><sub>p</sub>(T) down to 2 K. Moreover, combination of the bulk static susceptibility, heat capacity and <sup>7</sup>Li NMR studies indicates a complicated temperature transformation of the magnetic system. We observe a development of a cluster spin glass, where the Ising-like Ni<sup>2+</sup> 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 <sup>7</sup>Li NMR spectrum. |
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