Structural Chemistry and Spin-Glass Behaviour of Nd₁₈Li₈Fe₄TiO₃₉
Nd₁₈Li₈Fe₄TiO₃₉ has been synthesised and characterised by neutron powder diffraction, X-ray absorption spectroscopy, Mössbauer spectroscopy and magnetometry. the cubic structure (Pm3-n, a=11.97227(8) Å) is based on intersecting <1 1 1> chains comprised of alternating octahedral and trigonal-prismatic coordination sites. These chains lie within hexagonal-prismatic cavities formed by a Nd-O framework. The larger of the two crystallographically distinct octahedral sites, 8e, is occupied by iron, titanium and lithium in a ratio of 76:20:4; the smaller, 2a, is occupied by iron and titanium in a ratio of 79:21. the trigonal-prismatic site, 16i, is occupied by lithium and iron in a ratio of 98:2. The cations on the 2a sites are assigned as Ti4+ and low-spin Fe4+, and those on the 16i sites as Li+ and Fe3+. The 8e sites are thought to be occupied by Li+, Fe3+ and Ti3+ Nd₁₈Li₈Fe₄TiO₃₉ undergoes a transition to a spin-glass state at 4.25(5) K.
N. Thammajak et al., "Structural Chemistry and Spin-Glass Behaviour of Nd₁₈Li₈Fe₄TiO₃₉," Journal of Solid State Chemistry, vol. 187, no. 3, pp. 75-82, Elsevier, Jan 2012.
The definitive version is available at http://dx.doi.org/10.1016/j.jssc.2011.12.029
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