Magnetic properties of orthorhombic fluorite-related oxides Ln3SbO7 (Ln=rare earths)

Abstract

Ternary rare earth antimonates Ln 3 SbO 7 (Ln = rare earths) were prepared and their structures were determined by x-ray diffraction measurements. They crystallize in an orthorhombic superstructure of cubic fluorite (space group Cmcm for Ln = La, Pr, Nd; C222 1 for Ln = Nd ~ Lu), in which Ln 3+ ions occupy two different crystallographic sites (the 8-coordinated and 7-coordinated sites). Their magnetic properties were characterized by magnetic susceptibility and specific heat measurements from 1.8 to 400 K. The Ln 3 SbO 7 (Ln = Nd, Gd -Ho) compounds show an antiferromagnetic transition at 2.2 ~ 3.2 K. Sm 3 SbO 7 and Eu 3 SbO 7 show van Vleck paramagnetism. Measurements of the specific heat down to 0.4 K for Gd 3 SbO 7 and the analysis of the magnetic specific heat indicate that the antiferromagnetic ordering of the 8-coordinated Gd ions occur at 2.6 K, and the 7-coordinated Gd ions order at a furthermore low temperature.3

Magnetic properties and structural transitions of orthorhombic fluorite-related compounds Ln3MO7 (Ln=rare earths, M=transition metals)

“…This experimental result suggests that the anomalies observed at 0.8 and 2.5 K are due to the antiferromagnetic ordering of Sm 3+ ions independently in the 8-coordinated Sm(1) and 7-coordinated Sm(2) sites, respectively. Similar "two-step" antiferromagnetic transitions have been found in Ln 3 TaO 7 (Ln = Nd, Tb) [24], Ln 3 NbO 7 (Ln = Nd, Tb) [38], and Gd 3 SbO 7 [40]. …”

Optically induced effects in nano-crystallized PbO–Sb2O3–B2O3:Pr2O3 glasses

“…In such type of crystal phases, Sb 5+ ions occupy octahedral positions and participate in the glass network with SbO 6 structural units. The Pr 3 SbO 7 crystallites consist of the chains of SbO 6 and deformed PrO 8 structural units in alternate parallel planes [12,28]. Based on these arguments, an illustration of structural fragmentation of Pr 3 SbO 7 crystalline phase is shown in Fig.…”

“…These Sb 5+ ions participate in the glass network forming with Sb 5+ O 4 structural units and likely to link with BO 4 structural units in PbO-Sb 2 O 3 -B 2 O 3 glass ceramic network [11]. There are also reports suggesting that the Sb 5+ ions especially in the glasses mixed with rare earth ions form the crystals of the type Ln 3 SbO 7 in which these ions occupy octahedral sites [12]. The local structure of Sb 5+ ions that participate in the glass network with SbO 6 structural units is expected to be more asymmetric (it is the same as local charge density non-centrosymmetry determining the first order nonlinear optical susceptibilities).…”

Color - Tunable Phosphors in Weberite Type System, La3 SbO7 :Bi3+ , Eu3+ for Near-UV LED Applications

“…Crystal structure of Ln 3 SbO 7 (Ln=La−Dy) and magnetic properties of ternary Ln 3 SbO 7 (Ln=Rare earths) were reported by Siqueira et al . and Hinatsu et al . respectively.…”

“…It crystallizes into orthorhombic structure with Cmcm space group. According to Hinatsu et al . the unit cell for oxides have the general formula M 4 4+ O 8 in which four tetravalent ions are replaced by three trivalent ions (Ln) and one pentavalent ion (M).…”