Magnetic and Magnetocaloric Properties of the ALnSbO Lanthanide Oxides on the Frustrated Lattice.

Frustrated lanthanide oxides are promising candidates for cryogen-free magnetic refrigeration due to their suppressed ordering temperatures and high magnetic moments. While much attention has been paid to the garnet and pyrochlore lattices, the magnetocaloric effect in frustrated face-centered cubic () lattices remains relatively unexplored. We previously showed that the frustrated double perovskite BaGdSbO is a top-performing magnetocaloric material (per mol Gd) because of its small nearest-neighbor interaction between spins.

Free-Spin Dominated Magnetocaloric Effect in Dense Gd Double Perovskites.

Frustrated lanthanide oxides with dense magnetic lattices are of fundamental interest for their potential in cryogenic refrigeration due to a large ground state entropy and suppressed ordering temperatures but can often be limited by short-range correlations. Here, we present examples of frustrated oxides, BaGdSbO and SrGdSbO, and the new site-disordered analogue CaGdSbO ([CaGd] [CaSb] O), in which the magnetocaloric effect is influenced by minimal superexchange ( ∼ 10 mK). We report on the crystal structures using powder X-ray diffraction and the bulk magnetic properties through low-field susceptibility and isothermal magnetization measurements.

Intercalates of BiSe studied in situ by time-resolved powder X-ray diffraction and neutron diffraction.

Intercalation of lithium and ammonia into the layered semiconductor BiSe proceeds via a hyperextended (by >60%) ammonia-rich intercalate, to eventually produce a layered compound with lithium amide intercalated between the bismuth selenide layers which offers scope for further chemical manipulation.

Impact of Orientational Glass Formation and Local Strain on Photo-Induced Halide Segregation in Hybrid Metal-Halide Perovskites.

Band gap tuning of hybrid metal-halide perovskites by halide substitution holds promise for tailored light absorption in tandem solar cells and emission in light-emitting diodes. However, the impact of halide substitution on the crystal structure and the fundamental mechanism of photo-induced halide segregation remain open questions. Here, using a combination of temperature-dependent X-ray diffraction and calorimetry measurements, we report the emergence of a disorder- and frustration-driven orientational glass for a wide range of compositions in CHNHPb(Cl Br ).

Comparison of the ionic conductivity properties of microporous and mesoporous MOFs infiltrated with a Na-ion containing IL mixture.

IL@MOF (IL: ionic liquid; MOF: metal-organic framework) materials have been proposed as a candidate for solid-state electrolytes, combining the inherent non-flammability and high thermal and chemical stability of the ionic liquid with the host-guest interactions of the MOF. In this work, we compare the structure and ionic conductivity of a sodium ion containing IL@MOF composite formed from a microcrystalline powder of the zeolitic imidazolate framework (ZIF), ZIF-8 with a hierarchically porous sample of ZIF-8 containing both micro- and mesopores from a sol-gel synthesis. Although the crystallographic structures were shown to be the same by X-ray diffraction, significant differences in particle size, packing and morphology were identified by electron microscopy techniques which highlight the origins of the hierarchical porosity.

Magnetic Properties of Quasi-One-Dimensional Lanthanide Calcium Oxyborates CaO(BO).

This study examines the lanthanide calcium oxyborates CaO(BO) ( = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Yb). The reported monoclinic structure (space group ) was confirmed using powder X-ray diffraction. The magnetic ions are situated in well-separated chains parallel to the axis in a quasi-one-dimensional array.