Magnetic oxygen stored in quasi-1D form within BaAl2O4 lattice

Abstract

Inorganic materials that enable a link between the storage and release of molecular oxygen offer a fertile ground in continuous quest for the applications that can potentially reduce energy consumption and thus minimize adverse effects on the environment. Herein, we address reversible intake/release of an oxygen within the BaAl2O4 material as evidenced by unexpected magnetic ordering. Magnetic measurements unveil that an oxygen is stored in the form of condensed matter, creating a kind of low dimensional, chain-like assembly within the tunnels of BaAl2O4 structure. We demonstrate that oxygen is adsorbed simply by staying in air, at ambient conditions, and released relatively quickly by staying in the He or other gas atmosphere of several millibars pressure even at 300 K.

Structural Behavior and Spin-State Features of BaAl2O4 Scaled through Tuned Co3+ Doping

“…The χ· T ( T ) dependence for all samples looks quite similar: in the ∼50–298 K range, the χ ·T values remain almost constant (sample S0) or slightly decrease (samples S1 and S2) on decreasing the temperature, and as the temperature is lowered below ∼50 K, they decrease considerably on cooling down to 2 K. The broad peak around 50 K indicates the presence of oxygen. Namely, the great affinity of pure BaAl 2 O 4 for oxygen is firmly established by our group, demonstrating the material’s extraordinary magnetic response at temperatures below ∼60 K . The magnetic states of Co 3+ -doped samples discussed in this study are expected to give rise to a paramagnetic contribution in the magnetization signal due to the small amount of magnetic Co 3+ substituted within the diamagnetic BaAl 2 O 4 matrix.…”

“…Specifically, the band gap of E g = 6.5 eV and a small permittivity of ε′ = 14 at room temperature enable a strong localization of the photoexcited carriers. , These potential benefits are extensively used in the fabrication of a wide array of consumer products such as fluorescent lamps, light-emitting diodes, field emission displays, plasma display panels, fiber amplifiers, and dispenser cathodes . This especially refers to doped BaAl 2 O 4 materials as doping is a valuable strategy for modulating and/or creating new properties of a BaAl 2 O 4 host in a controlled manner, thus offering an optimal combination of electrical, optical, and microstructural properties. , Our earlier study extended the field of BaAl 2 O 4 applications to the oxygen-driven storage capacity of this material, initiated by the unique antiferromagnetic transition in crystalline oxygen . The BaAl 2 O 4 crystallizes in a hexagonal assembly at room temperature (RT), within P 6 3 (space group (s.g.) no.…”

“…173 with lattice constants a = 10.449(1) Å and c = 8.793(1) Å) − and P 6 3 22 (s.g. no. 182 with lattice constants a = 5.2211(1) Å and c = 8.7898(1) Å) symmetries, depending on the subtle preparation conditions. The hexagonal packing described by the space group P 6 3 construes two different barium sites, Ba1 and Ba2, positioned on two inequivalent crystallographic sites 2 a and 6 c , respectively, and coordinated by nine oxygen ions with average Ba–O distances of 2.85 Å for the Ba1 site and 2.95 Å for the Ba2 site.…”

“…7,8 Our earlier study extended the field of BaAl 2 O 4 applications to the oxygen-driven storage capacity of this material, initiated by the unique antiferromagnetic transition in crystalline oxygen. 9 The BaAl 2 O 4 crystallizes in a hexagonal assembly at room temperature (RT), within P6 8.793(1) Å) 10−12 and P6 3 22 (s.g. no. 182 with lattice constants a = 5.2211(1) Å and c = 8.7898(1) Å) 9 symmetries, depending on the subtle preparation conditions.…”

Evolution of Free Volumes in Polycrystalline BaGa2O4 Ceramics Doped with Eu3+ Ions

“…Most investigations of such material are limited to X-ray diffraction (XRD), optical studies, etc. [15][16][17][18][19]. Nevertheless, the doping of such ceramics not only leads to the modification of their luminescent properties and changes in phase composition, but also causes structural transformation [20,21].…”