Remarkable Magneto-Optical Properties of Europium Selenide Nanoparticles with Wide Energy Gaps

Abstract

The enhanced magneto-optical properties of nanoscaled lanthanide chalogenide semiconductors which have a wide energy gap were observed at around 500 nm for the first time. The nanoscaled semiconductors, Eu(1-x)Se nanoparticles 1 (cubic shapes) and 2 (spherical shapes), were synthesized by the thermal reduction of Eu(III) ion with organic ligands containing Se atoms. The resulting Eu(1-x)Se nanoparticles were characterized by X-ray diffraction, high-resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, superconducting quantum interference devices magnetometer, and microwave induced plasma atomic emission spectroscopy measurements. The particle grain sizes of 1 and 2 were estimated to be 11 and 20 nm, respectively. The concentration-normalized Veldet constants (the magnitude of the Faraday effect) of Eu(1-x)Se nanoparticles were much larger than those of corresponding bulk EuSe and EuS nanoparticles.

Crystal growth of nanoscaled europium selenide having characteristic crystal shapes

“…However, in XRD signals of EuSe nanocrystals 2, we found that we observed the signals at around 20 • and 30 • that were not assigned to EuSe signals. The signal at around 30 • is similar to that of EuSe2 (30.18 • ) [12]. We propose that the small EuSe2 might be existed on the surface of EuSe nanoparticles 2.…”

“…These magneto-optical properties are strongly dependent on their sizes [9]. Especially the photophysical properties of nano-sized materials are affected by size, shape, surface conditions and surrounding environment of the crystals [11,12].…”

“…Recently, we have reported on the enhancement of EuSe nanocrystals' magneto-optical properties, which are significantly dependent on the size and shape of each crystal [12]. These crystal grain sizes were calculated using the Scherer equation based on their XRD spectrum, and were estimated to be 11 and 20 nm.…”

Photofunctional Lanthanoid Complexes, Coordination Polymers, and Nanocrystals for Future Photonic Applications

“…EuSe nanocrystals display antiferromagnetic behavior (Néel point: T N = 4.6 K). 188 This Néel point of the EuSe nanocrystals agrees with that of bulk EuSe. 211 The saturation magnetization of EuSe nanocrystals normalized by the concentration of EuSe at 1.8 K was found to be 4.6.…”

A Simple Reducing Approach Using Amine To Give Dual Functional EuSe Nanocrystals and Morphological Tuning

“…[13] Their 4f-5d electronic transitions and spin configuration lead to unique magneto-optical properties. [14] During the past a few years, several research groups reported various routes to prepare the EuX NCs, such as with high temperature reduction, thermal or optical decomposition of single-source precursors, and a liquid-phase synthesis. [15][16][17][18] However these methods usually required special instruments and extra ligands for Eu 3+ , which were time-consuming with the product; meanwhile, the resulting EuX NCs exhibited poor optical and magnetic properties, with little potential in applications.…”