Scheelite related compounds with general formula M n (XO 4 ) m are the subject of hefty interest owing to their optical properties, stability and relatively simple preparation. Eu 3+ -containing scheelites are considered as redemitting phosphors and the main factors affecting their luminescence are thought to be chemical composition and particle size while the influence of their structure is generally ignored. Here we report eight compounds from the Na x Eu (2Àx)/3 MoO 4 series prepared by conventional solid-state reaction and present a detailed analysis of their crystal structures. Six of them have modulated structures, a common feature of SRCs, in which dopant Eu 3+ ions are orderly distributed. Moreover, different amounts of Eu 3+ dimers are detected in the modulated structures, characterized by weak satellite reflections appearing in the lower angle part of the XRD patterns. These reflections are indexed and incorporated into Rietveld's refinement using superspace (3 + 1)-dimension symmetry. The remarkable feature of the compounds is that the characteristic luminescence parameters, overall (Q Eu L ) and intrinsic (Q Eu Eu ) quantum yields, Eu( 5 D 0 ) lifetimes, and sensitization efficiencies (h sens ), correlate with the number of Eu 3+ aggregates, but not directly with the composition x of the materials. This provides an efficient tool for understanding and controlling the luminescence properties of scheelite related compounds.

The demand for ever-increasing density of information storage and speed of manipulation boosts an intense search for new magnetic materials and novel ways of controlling the magnetic bit. Here, we report the synthesis of a ferromagnetic photovoltaic CH3NH3(Mn:Pb)I3 material in which the photo-excited electrons rapidly melt the local magnetic order through the Ruderman–Kittel–Kasuya–Yosida interactions without heating up the spin system. Our finding offers an alternative, very simple and efficient way of optical spin control, and opens an avenue for applications in low-power, light controlling magnetic devices.

X-ray photon detection is important for a wide range of applications. The highest demand, however, comes from medical imaging, which requires cost-effective, high-resolution detectors operating at low photon flux, therefore stimulating the search for novel materials and new approaches. Recently, hybrid halide perovskite CH3NH3PbI3 (MAPbI3) has attracted considerable attention due to its advantageous optoelectronic properties and low fabrication costs. The presence of heavy atoms, providing a high scattering cross-section for photons, makes this material a perfect candidate for X-ray detection. Despite the already-successful demonstrations of efficiency in detection, its integration into standard microelectronics fabrication processes is still pending. Here, we demonstrate a promising method for building X-2 ray detector units by 3D aerosol jet printing with a record sensitivity of 2.2 x 10 8 µC Gyair -1 cm -2 when detecting 8 keV photons at dose-rates below 1 Gy/s (detection limit 0.12 Gy/s), a fourfold improvement on the best-in-class devices. An introduction of MAPbI3-based detection into medical imaging would significantly reduce health hazards related to the strongly ionizing Xrays photons.

Scheelite-type compounds with the general formula (A1,A2)(n)[(B1,B2)O(4)](m) (2/3 ≤ n/m ≤ 3/2) are the subject of large interest owing to their stability, relatively simple preparation, and optical properties. The creation of cation vacancies (□) in the scheelite-type framework and the ordering of A cations and vacancies can be a new factor in controlling the scheelite-type structure and properties. For a long time, cation-deficient Nd(3+):M(2/7)Gd(4/7)□(1/7)MoO(4) (M = Li, Na) compounds were considered as potential lasers with diode pumping. They have a defect scheelite-type 3D structure (space group I4(1)/a) with a random distribution of Li(+)(Na(+)), Gd(3+), and vacancies in the crystal. A Na(2/7)Gd(4/7)MoO(4) single crystal with scheelite-type structure has been grown by the Czochralski method. Transmission electron microscopy revealed that Na(2/7)Gd(4/7)MoO(4) has a (3 + 2)D incommensurately modulated structure. The (3 + 2)D incommensurately modulated scheelite-type cation-deficient structure of Na(2/7)Gd(4/7)MoO(4) [super space group I4 (α-β0,βα0)00] has been solved from single-crystal diffraction data. The solution of the (3 + 2)D incommensurately modulated structure revealed the partially disordered distribution of vacancies and Na and Gd cations. High-temperature conductivity measurements performed along the [100] and [001] orientation of the single crystal revealed that the conductivity of Na(2/7)Gd(4/7)MoO(4) at T = 973 K equals σ = 1.13 × 10(-5) Ω(-1) cm(-1).

Potassium neodymium molybdenum oxide, KNd(MoO 4 ) 2 , has been synthesized by the solid-state method. The structure and microstructure have been studied by X-ray powder diffraction and transmission electron microscopy (TEM). TEM revealed that the KNd(MoO 4 ) 2 structure is incommensurately modulated. The scheelite-like structure of KNd(MoO 4 ) 2 has been refined from X-ray powder diffraction intensities in the (3 + 1)D superspace group I2/b(R 0)00 with a ) 5.5202(2) Å, b ) 5.33376(5) Å, c ) 11.8977(3) Å, γ ) 90.9591(7)°, and modulation vector q ) 0.57789(4)a* -0.14748(6)b* (R P ) 3.09%, R wP ) 4.04%). The ordering of the K and Nd cations appears to be the primary parameter of the structure modulations. The compositional wave of the {KMoO 4 } and {NdMoO 4 } distribution is observed in the ab structure projection. The incommensurability of the compositional wave direction with respect to the a and b lattice constants is regarded as the origin of the incommensurate structure modulations.