Magnetic Gd3 Research Articles

Low-temperature magnetic interactions in the “butterfly”-type {Fe3GdO2} compound: The persistence of magnetic chains

Heat capacity measurements on the Ln = Gd case of the butterfly molecule series [Fe3Ln(μ3–O)2 (CCl3COO)8(H2O)(THF)3], in brief {Fe3LnO2}, are presented. In the previously studied {Fe3YO2} butterfly, where the magnetic properties stem only from the Fe3+ ions, magnetic chains of spin-5/2 Fe3Y clusters had been identified and described. The substitution of the nonmagnetic Y3+ ion by the magnetic Gd3+ adds magnetic interactions to the clusters, but not magnetic anisotropy. The heat capacity measurement shows an excess over the contribution of the antiferromagnetically coupled Fe3Gd magnetic clusters at very low temperature, which can be described as magnetic spin-1 chains using a Blume–Capel model. The intercluster interaction constant Jch=−55(5) mK is very similar to that of {Fe3YO2}, which shows that the interaction is mainly controlled by the magnitude of the cluster’s magnetic moment.

Using lanthanide ions as magnetic and sensing probes for the detection of tetracycline from complex samples.

Tetracycline (TC) is a broad-spectrum antibiotic and has been added to animal feeds to grow livestock under healthy conditions, making it important to have effective methods for rapidly detecting TC in complex samples. In this study, a novel method that uses lanthanide ions (i.e. Eu3+ and Gd3+) as magnetic and sensing probes for the detection of TC from aqueous samples is explored. When dissolving Gd3+ in tris(hydroxymethyl)aminomethane (Tris) buffer at pH 9, magnetic Gd3+-Tris conjugates can be readily generated. The magnetic Gd3+-Tris conjugates possess trapping capacity toward TC from sample solutions via the chelation of Gd3+ and TC. Eu3+ is used as the fluorescence sensing probe against TC on the Gd3+-TC conjugates via the antenna effect. The fluorescence response derived from Eu3+ is increased with the increase of TC trapped on the Gd3+-based probes. The linear dynamic range against TC ranges from 20 to 320 nM, whereas the limit of detection toward TC is ~2 nM. Furthermore, the developed sensing method can be employed for the visual assay of TC with a concentration above ~0.16 μM under UV light illumination in the dark. Furthermore, we have demonstrated the applicability of the developed method to quantify TC in a chicken broth sample with complex matrix. Our developed method offers several advantages, including high sensitivity and good selectivity, for the detection of TC in complex samples.

Effect of Nonconstituent Additive Ions on the Controlled Crystallization of Lanthanide-Based Preyssler Polyoxometalates.

Preyssler-type polyoxometalates (POMs) encapsulating lanthanide ions have been shown to provide ideal examples of single-molecule magnets and spin-qubits. However, the advances in this area are limited by the quality and size of the crystals. In this work, the role of additives ions in the crystallization of these POMs from aqueous solutions has been investigated. More specifically, we have studied the influence of Al3+, Y3+, and In3+ on the crystallization process of K12[MP5W30O110] (where M = Gd and Y). The results show that the concentration of these ions in the solution plays an important role in controlling the crystallization rate of the grown POM crystals leading to a significant increase in their size, while showing very little or no tendency to be incorporated into the structure. This has allowed us to obtain pure Gd or Y crystals, as well as diluted magnetic crystals formed by the diamagnetic Y3+ POM doped with the magnetic Gd3+ ion.

Application of High-Frequency Electron Paramagnetic Resonance/Electron Spin Echo for the Identification of the Impurity Composition and Electronic Structure of Ceramics Based Garnets

Electron paramagnetic resonance (EPR) spectra of Ce3+, Yb3+, Cr3+, and Gd3+ impurity ions in yttrium aluminum garnet Y3Al5O12 (YAG) ceramics were detected and identified at frequency of 94 GHz. The advantage of measuring the EPR spectra in the high-frequency range compared to the standard EPR technique is shown, which makes it possible to separate the EPR spectra characterized by different anisotropic g-factors and also to isolate the EPR signals due to the splitting of the fine structure for centers with high-spin states. In ceramics with a high content of magnetic Gd3+ ions, EPR and electron spin echo (ESE) spectra of multi-ionic gadolinium complexes were observed, and EPR spectra of complexes with the maximum number of exchange-coupled gadolinium ions are seen at low temperatures. The temperature dependences of the EPR spectra indicates ferromagnetic ordering of exchange-coupled complexes of gadolinium.