62462-49-1Relevant articles and documents
Solid-State and Nanoparticle Synthesis of EuSxSe1- x Solid Solutions
Dalafu, Haydee A.,Rosa, Nicholas,James, Derak,Asuigui, Dane Romar C.,McNamara, Michael,Kawashima, Akira,Omagari, Shun,Nakanishi, Takayuki,Hasegawa, Yasuchika,Stoll, Sarah L.
, p. 2954 - 2964 (2018)
Europium chalcogenide alloys, EuSxSe1-x, have been synthesized both in the solid-state and as colloidal nanoparticles; the composition, structure, magnetism, and optical band gaps have been characterized. The goal was to observe the consequences of selenium concentration on the electronic structure as evidenced by the optical and magnetic properties and whether these properties are maintained in the nanomaterials. Both solid-state and nanoparticle alloys obey Vegard's law with a systematic change in cell constant as confirmed by the powder X-ray diffraction. The bulk materials form homogeneous alloys that exhibit a linear change in both magnetic and optical properties as a function of composition. A synthetic method to prepare nanoalloys with a wide range of S:Se ratio has been developed. The nanoalloys are homogeneous, and EDS mapping of single nanoparticles indicates relatively uniform S and Se composition across the nanocrystals. The magnetic properties of the nanoparticles appear to parallel those in the solid-state. Although the composition is an effective tool to tune to the optical band gap in the solid-state alloys with a linear change in Eg with composition, the nanoparticle optical band gaps appeared to be shifted, which we attribute to the presence of an amorphous selenium phase. The study of the properties of colloidal alloys highlights the importance of the mechanism of nanoparticle formation to control composition and purity.
Regularities of the property changes in the compounds EuLnCuS3 (Ln = La-Lu)
Ruseikina, Anna V.,Chernyshev, Vladimir A.,Velikanov, Dmitriy A.,Aleksandrovsky, Aleksandr S.,Shestakov, Nikolay P.,Molokeev, Maxim S.,Grigoriev, Maxim V.,Andreev, Oleg V.,Garmonov, Alexander A.,Matigorov, Alexey V.,Melnikova, Ludmila V.,Kislitsyn, Anatoliy A.,Volkova, Svetlana S.
, (2021/05/04)
This work contains the results of complex experimental research of the compounds EuLnCuS3 (Ln = La-Lu) enhanced by the DFT calculations. It is aimed at the data replenishment with particular attention to the revelation of regularities in the property changes, in order to extend the potential applicability of the materials of the selected chemical class. The ab initio calculations of the fundamental vibrational modes of the crystal structures were in good agreement with experimental results. The wavenumbers and types of the modes were determined, and the degree of the ion participation in the modes was also estimated. The elastic properties of the compounds were calculated. The compounds were found out to be IR-transparent in the range of 4000–400 cm–1. The estimated microhardness of the compounds is in the range of 2.68–3.60 GPa. According to the DSC data, the reversible polymorphous transitions were manifested in the compounds EuLnCuS3 (Ln = Sm, Gd-Lu): for EuSmCuS3 Tα?β = 1437 K, ΔНα?β = 7.0 kJ·mol-1, Tβ?γ = 1453 K, ΔНβ?γ = 2.6 kJ·mol-1; for EuTbCuS3 Tα?β = 1478 K, ΔНα?β = 1.6 kJ·mol-1, Tβ?γ = 1516 K, ΔНβ?γ = 0.9 kJ·mol-1, Tγ?δ = 1548 K, ΔНγ?δ = 1.6 kJ·mol-1; for EuTmCuS3 Tα?β = 1543 K, Tβ?γ = 1593 K, Tγ?δ = 1620 K; for EuYbCuS3 Tα?β = 1513 K, Tβ?γ = 1564 K, Tγ?δ = 1594 K; for EuLuCuS3 Tα?β = 1549 K, Tβ?γ = 1601 K, Tγ?δ = 1628 K. In the EuLnCuS3 series, the transition into either ferro- or ferrimagnetic states occurred in the narrow temperature range from 2 to 5 K. The tetrad effect in the changes of incongruent melting temperature and microhardness conditioned on rLn3+ as well as influencing of phenomenon of crystallochemical contraction were observed. For delimiting between space groups Cmcm and Pnma in the compounds ALnCuS3, the use of the tolerance factor t’ = IR(A)·IR(C) + a×IR(B)2 was verified.
Molten alkali halide flux growth of an extensive family of noncentrosymmetric rare earth sulfides: Structure and magnetic and optical (SHG) properties
Usman, Mohammad,Smith, Mark D.,Morrison, Gregory,Klepov, Vladislav V.,Zhang, Weiguo,Shiv Halasyamani,Loye, Hans-Conrad zur
, p. 8541 - 8550 (2019/08/21)
Twenty new alkali rare earth thiosilicates and thiogermanates with the general formula ALnTS4 (A = alkali metal, Ln = lanthanide, and T = Si, Ge) were grown as X-ray diffraction-quality single crystals from molten alkali chloride fluxes. These include KNdSiS4, KPrSiS4, RbLnSiS4 (Ln = Ce, Pr, Nd, Gd, Tb, Dy, and Ho), RbLaGeS4, CsLnSiS4 (Ln = La, Pr, and Nd), and CsLnGeS4 (La, Ce, Pr, Nd, Eu, Gd, and Tb). Herein, we discuss the use of a molten chloride flux growth approach for the preparation of the title compounds and their structure determination via single-crystal X-ray diffraction. In addition, we comment on the magnetic properties of RbNdSiS4, CsNdSiS4, CsNdGeS4, and CsGdGeS4, which were found to be paramagnetic for T = 2?300 K and exhibited negative Weiss temperatures with no obvious antiferromagnetic transition down to 2 K. The optical properties of CsLaGeS4 and CsNdTS4(T = Si, Ge) were measured by UV?vis spectroscopy. Second harmonic generation measurements performed on CsLaGeS4 confirmed the crystallization of the compound in the noncentrosymmetric orthorhombic space group, P212121; CsLaGeS4 was found to be SHG-active with nearly half the intensity of α-SiO2 upon irradiation with a Nd:YAG 1064 nm laser, and a semiconductor exhibiting a band gap of 3.60 eV based on UV? vis diffuse reflectance measurements.
