Magnetic and Electron Spin Relaxation Properties of (Gd x Y1−x )2O3 (0 ≤ x ≤ 1) Nanoparticles Synthesized by the Combustion Method. Increased Electron Spin Relaxation Times with Increasing Yttrium Content

• Published in: Journal of physical chemistry. C Vol. 115; no. 13; pp. 5469 - 5477
• Main Authors: Gustafsson, Håkan, Ahrén, Maria, Söderlind, Fredrik, Córdoba Gallego, José M, Käll, Per-Olov, Nordblad, Per, Westlund, Per-Olof, Uvdal, Kajsa, Engström, Maria
• Format: Journal Article
• Language: English
• Published: American Chemical Society 07.04.2011
• Subjects: C: Nanops and Nanostructures
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp111368t

The performance of a magnetic resonance imaging contrast agent (CA) depends on several factors, including the relaxation times of the unpaired electrons in the CA. The electron spin relaxation time may be a key factor for the performance of new CAs, such as nanosized Gd2O3 particles. The aim of this work is, therefore, to study changes in the magnetic susceptibility and the electron spin relaxation time of paramagnetic Gd2O3 nanoparticles diluted with increasing amounts of diamagnetic Y2O3. Nanoparticles of (Gd x Y1−x )2O3 (0 ≤ x ≤ 1) were prepared by the combustion method and thoroughly characterized (by X-ray diffraction, transmission electron microscopy, thermogravimetry coupled with mass spectroscopy, photoelectron spectroscopy, Fourier transform infrared spectroscopy, and magnetic susceptibility measurements). Changes in the electron spin relaxation time were estimated by observations of the signal line width in electron paramagnetic resonance spectroscopy, and it was found that the line width was dependent on the concentration of yttrium, indicating that diamagnetic Y2O3 may increase the electron spin relaxation time of Gd2O3 nanoparticles.