Structure, conductivity and magnetism of orthorhombic and fluorite polymorphs in MoO-LnO (Ln = Gd, Dy, Ho) systems.

Phase-pure orthorhombic compositions at a Ln/Mo ratio ∼ 5.2-5.7 (Ln = Gd, Dy, Ho) have been obtained for the first time by prolonged (40-160 h) heat treatment of mechanically activated 5Ln2O3 + 2MoO3 (Ln = Gd, Dy, Ho) oxide mixtures at 1200 °C.

Evolution of Oxygen-Ion and Proton Conductivity in Ca-Doped LnZrO (Ln = Sm, Gd), Located Near Pyrochlore-Fluorite Phase Boundary.

SmCaZrO (x = 0, 0.05, 0.1) and GdCaZrO (x = 0.

Comparative Study of Electrical Conduction and Oxygen Diffusion in the Rhombohedral and Bixbyite LnMoO (Ln = Er, Tm, Yb) Polymorphs.

Electrical conduction and oxygen diffusion mobility in the bixbyite ( Ia3̅) and rhombohedral ( R3̅) polymorphs of the LnMoO (Ln = Er, Tm, Yb; Δ = δ, δ1, δ2; δ1 > δ2) heavy lanthanide molybdates, belonging to new, previously unexplored classes of potential mixed (ionic-electronic) conductors, have been studied in the range of 200-900 °C. The oxygen self-diffusion coefficient in bixbyite ( Ia3̅) YbMoO phase estimated by the temperature-programmed heteroexchange with CO was shown to be much higher than that for rhombohedral ( R3̅) RI (with large oxygen deficiency) and ( R3̅) RII (with small oxygen deficiency) LnMoO (Ln = Tm, Yb; Δ = δ1; δ1 > δ2) oxides. According to the activation energy for total conduction in ambient air, 0.

Proton and oxygen ion conductivity in the pyrochlore/fluorite family of LnCaScMO (Ln = La, Sm, Ho, Yb; M = Nb, Ta; x = 0, 0.05, 0.1) niobates and tantalates.

The tolerance factor is a good criterion to understand the structural transitions in LnCaScMO (Ln = La, Sm, Ho, Yb; M = Nb, Ta; x = 0, 0.05, 0.1).