MRI contrast agents based on dysprosium or holmium.

Profile analysis of powder neutron diffraction data: Its scope, limitations, and applications in solid state chemistry

van der Waals (vdW) magnetic insulators are of significance in both fundamental research and technological application, but most two-dimensional (2D) vdW magnetic systems are unstable and of high lattice symmetry. Stable 2D vdW magnetic insulators with anisotropic structure are needed to modulate the properties and unlock potential applications. Here we present a stable vdW antiferromagnetic material, CrOCl, with low-symmetry orthorhombic structure, and investigate systematically its magnetism, phase transition behavior, and optical anisotropy. Spin-phonon coupling effects are uncovered by the abnormal frequency shifts of Raman-active modes, suggesting the formation of a magnetic superstructure. The sizable abnormal change of interplanar spacing indicates the presence of a structural transition at around 27 K. Further in-plane vibrational, reflectional, and absorptional anisotropic properties are explored both experimentally and theoretically, revealing a highly polarization sensitive characteristic and linear dichroism in 2D CrOCl. Meanwhile, the particularly high polarization dependency of the second-harmonic generation and the nonlinear susceptibility of ∼2.24 × 10-11 m/V make it suitable in the field of polarization-dependent nonlinear optics. The findings on the intricate properties of 2D CrOCl lay foundations for future applications of low-symmetry vdW magnets in spin-dependent electronic and optoelectronic devices.

Magnetism and Optical Anisotropy in van der Waals Antiferromagnetic Insulator CrOCl

A general approach has been developed for the synthesis of monoclinic ErOOH and cubic Er2O3 structures with high yield and controlled size and shape via the solvo-hydrothermal reaction of erbium nitrate in water/ethanol/decanoic acid media. The monoclinic ErOOH phase was formed at relatively low temperature (120−140 °C); however, the cubic Er2O3 phase was obtained at higher temperature (160−180 °C). By simply tuning different experimental parameters, such as the reaction temperature, the concentration of decanoic acid and erbium precursor etc., different sizes from 3 nm to 3 μm, and a variety of shapes including cores/dots to spheres, wrinkle-surfaced spheres, flowers, dog bonds, wires, rods, bundles, straw sheaves, and brooms can be achieved. The particle size of products decreased from micro- to nanometer as the decanoic acid concentration increased from 0.038 to 0.190 M. Furthermore, by using anhydrous ethanol instead of water−ethanol solvents, the particle size significantly decreased from 18 nm spher...

S. Quézel

Papers

Preparation and magnetic properties of crocl

Crystal structure and magnetic structure of TbOOH

The magnetic structure of the monoclinic modification of ErOOH

Low temperature magnetic properties of the monoclinic modification of DyOOH