Magnetism and Electronic State of Iron Ions on the Surface and in the Core of TiO[sub.2] Nanoparticles

• Published in: Magnetochemistry 2023-08, Vol.9 (8)
• Main Authors: Yermakov, Anatoly Ye, Uimin, Mikhail A, Boukhvalov, Danil W, Minin, Artem S, Kleinerman, Nadezhda M, Naumov, Sergey P, Volegov, Aleksey S, Starichenko, Denis V, Borodin, Kirill I, Gaviko, Vasily S, Konev, Sergey F, Cherepanov, Nikolay A
• Format: Article
• Language: English
• Subjects: Electric properties; Electron paramagnetic resonance; Iron; Magnetic properties; Mössbauer spectroscopy; Nanoparticles; Spectra; Titanium dioxide
• ISSN: 2312-7481; 2312-7481
• DOI: 10.3390/magnetochemistry9080198

In this paper, the electron and magnetic state of iron placed either on the surface or in the core of TiO[sub.2] nanoparticles were investigated using magnetometric methods, electron paramagnetic resonance (EPR) and Mössbauer spectroscopy. It was demonstrated that the EPR spectra of TiO[sub.2] samples with iron atoms localized both on the surface and in the core of specific features depending on the composition and size of the nanoparticles. Theoretical calculations using the density functional theory (DFT) method demonstrated that the localization of Fe atoms on the surface is characterized by a considerably larger set of atomic configurations as compared to that in the core of TiO[sub.2] nanoparticles. Mössbauer spectra of the samples doped with Fe atoms both on the surface and in the core can be described quite satisfactorily using two and three doublets with different quadrupole splitting, respectively. This probably demonstrates that the Fe atoms on particle surface and in the bulk are in different unlike local surroundings. All iron ions, both on the surface and in the core, were found to be in the Fe[sup.3+] high-spin state.