Ludwigites: From natural mineral to modern solid solutions

Abstract

Ludwigites is a type of oxyborates compounds with BO 3 groups, which have low-dimensional elements: stairs, zigzag walls, tapes. Such structural features influence on the physical properties of the compounds and cause charge ordering, the existence of two magnetic subsystems, ordered at different temperatures in the perpendicular direction, the quasi-one-dimensional magnetism, spin-glass state. In this survey, we have summarized all known experimental and theoretical studies and analyzed the proposed by the authors mechanisms of phase transitions in the ludwigite structure oxyborates.

Investigations of the heterometallic ludwigite Ni2AlBO5

“…In the previous reports on BaMnF 4 [29],MnF 2 [30] and MnO [31] the temperature dependence of the lattice dielectric constant has been fitted by modified Barrett equation of the form T = (0)+A/[exp( ω 0 /k B T)-1] where (0) is the expected dielectric constant at 0K, A is a coupling constant and ω 0 is the lowest mean frequency of the final states in the optical phonon branch. A fit using this modified Barrett formalism is indicated by a solid line in Figure (5), yielding (0)=22.664(±0.0008), A=0.80(±0.06), ω 0 =202(±6)cm −1 . It would be interesting to perform Raman or infrared measurements on this system to evaluate if any of the observed modes corresponds to the value which we have deduced from our fitting procedure.…”

Structural and spectroscopic investigation of the charge-ordered, short-range ordered, and disordered phases of the Co$_3$O$_2$BO$_3$ ludwigite

“…Additionally, there is a possible spin-state crossover of the Co 3+ ions, which are presumably in a low-spin configuration in the magnetically ordered phase (T ≤ 43 K) and in a high-spin configuration at higher temperatures (T 200 K) where the Curie-Weiss paramagnetic behavior is established [12,14,15]. Indeed, the combination of low dimensional units and mixed valence states leads to a number interesting physical phenomena in ludwigites [16,17], such as dimerized states [9], structural and charge-ordering transitions [9,10,14,18,19], spin-glass states [20][21][22][23][24][25][26][27][28], and multiferroicity [29]. Also, these oxyborates have been tested as high-performance electrodes for lithium-ion and sodium-ion batteries [30][31][32][33], low frequency oscillators [34,35], and as oxygen evolution reaction (OER) electrocatalyst [36].…”

Crystal Growth, Magnetic Properties and Analysis of Possible Magnetic Ordering of Ni5Sn(BO5)2 with Ludwigite Structure

“…Oxyborates represent a wide group of compounds, and these have been studied for a considerable time . Although oxyborates grow in different structures, almost all of these structures include low‐dimensional elements such as walls, ladders, chains, and ribbons .…”

“…The ludwigites are one of the most interesting groups of oxyborates. Compounds with a ludwigite structure have been widely studied, although it is still unclear which interactions are important in the formation of magnetic ordering in many compounds . For example, the magnetic properties change dramatically when Sn is substituted for Ti in Co 5 Ti(BO 5 ) 2 .…”