Structural, Spectroscopic, and Magnetic Properties of Eu<sup>3+</sup>-Doped GdVO<sub>4</sub> Nanocrystals Synthesized by a Hydrothermal Method
作者:Agata Szczeszak、Tomasz Grzyb、Zbigniew Śniadecki、Nina Andrzejewska、Stefan Lis、Michał Matczak、Grzegorz Nowaczyk、Stefan Jurga、Bogdan Idzikowski
DOI:10.1021/ic500354t
日期:2014.12.1
New interesting aspects of the spectroscopic properties, magnetism, and method of synthesis of gadolinium orthovanadates doped with Eu3+ ions are discussed. Gd-1-xEuxVO(4) (x = 0, 0.05, 0.2) bifunctional luminescent materials with complex magnetic properties were synthesized by a microwave-assisted hydrothermal method. Products were formed in situ without previous precipitation. The crystal structures and morphologies of the obtained nanomaterials were analyzed by X-ray diffraction and transmission and scanning electron microscopy. Crystallographic data were analyzed using Rietveld refinement. The products obtained were nanocrystalline with average grain sizes of 70-80 nm. The qualitative and quantitative elemental composition as well as mapping of the nanocrystals was proved using energy-dispersive X-ray spectroscopy. The spectroscopic properties of red-emitting nanophosphors were characterized by their excitation and emission spectra and luminescence decays. Magnetic measurements were performed by means of vibrating sample magnetometry. GdVO4 and Gd0.8Eu0.2VO4 exhibited paramagnetic behavior with a weak influence of antiferromagnetic couplings between rare-earth ions. In the substituted sample, an additional magnetic contribution connected with the population of low-lying excited states of europium was observed.