Electronic Structure, Electrical and Magnetic Properties of RMo₈O₁₄ Compounds (R = La, Ce, Pr, Nd, Sm) Containing Bicapped Mo₈ Clusters

Abstract

Magnetic and electrical resistivity properties of RMo(8)O(14) (R = La, Ce, Pr, Nd, Sm) compounds containing different bicapped-octahedral Mo(8) clusters are discussed. Extended Hückel (EH) molecular calculations were carried out in order to study the influence of the position of metal capping atoms on the electronic structure of different Mo(8) isomers. Different optimal metal electron counts are possible for these clusters. Periodic density functional calculations confirm the molecular character of these compounds and allow the understanding of their semiconducting and magnetic properties.

Thermoelectric properties of molybdenum oxides LnMo8O14 (Ln = La, Ce, Pr, Nd and Sm)

“…Our band structure calculation indicates that LaMo 8 O 14 is a semiconductor with a direct band gap of 0.05 eV at the point, which is quite comparable to the result of Gautier et al [34]. Later, semiconducting behavior was confirmed by the electrical conductivity measurement.…”

“…The electrical and magnetic properties of LnMo 8 O 14 (Ln = La, Ce, Pr, Nd and Sm) single crystals have been previously measured below room temperature [34,35]. In this article, thermoelectric properties of these molybdenum oxides obtained from bulk materials will be discussed.…”

“…The densities of states (DOS) for this compound have been described elsewhere [34], so only the band structure results will be discussed here. Since all atomic sites in the structure of LaMo 8 O 14 are fully occupied, the model of this compound chosen for the calculation was taken directly from the single crystal structure determination [17] with the Pbcn symmetry.…”

Phase diagram and influence of defects in the double perovskites

“…In addition, compounds of the type RMo 8 O 14 (R a rare earth͒ show no magnetic contribution from the Mo ions, which suggest weak magnetic interactions in Mo ions. 25 We do not consider additional interactions at O sites. 21 The leading interactions between different sites not considered here are probably superexchange couplings between Fe ions at the Fe sublattice 20 ͑as discussed before, magnetic couplings between an Fe ion at a Mo site and its Fe neighbors are taken into account͒.…”

Investigation of optical and electrical properties of the semiconducting α-KZnPO4 compound

“…6,7 Moreover, researchers have put the light on the specific characteristic of the orthophosphate that comprehended a monovalent cation thanks to their significant ionic conductivity and potential value as solid electrolytes for rechargeable “alkaline batteries”. 8–10 In addition the crystal structure diversity is a principal feature for this family of compounds that are controlled by the stereo-chemical behaviors of the A and B cations. Among the different structures, we are interested in the tridymite type materials that possess a strong correlation between structural, physical and electrochemical properties.…”