caa a22 4500 605545545 CHVBK 20210128100936.0 cr unu---uuuuu 210128e20150701xx s 000 0 eng 10.1007/s00723-015-0676-1 doi (NATIONALLICENCE)springer-10.1007/s00723-015-0676-1 EPR Evidence of Unusual Dopant Valency States in Nanocrystalline Er-doped CeO2 [Elektronische Daten] [R. Rakhmatullin, L. Aminov, I. Kurkin, A. Pöppl] The structure and oxidation state of the Er dopant cation in CeO2 single crystal and nanocrystals with size ranging from 22 to 300nm are studied using electron paramagnetic resonance (EPR) spectroscopy at X- and at Q-band near liquid-He temperatures. Besides the expected EPR line due to Er3+ in cubic sites in the lattice, unusual EPR lines with g values around 14 and 20 are observed in nanocrystalline CeO2. The appearance of these lines suggests the formation of non-Kramers Er2+, Er4+ ions, which becomes increasing favorable with decreasing nanoparticle size. Formation of rare earth ions with such unusual oxidation states in nanoparticles can be exploited in tuning their catalytic activity and optical properties. Springer-Verlag Wien, 2015 Rakhmatullin R. MRS Laboratory, Kazan Federal University, Kremlevskaya 18, 420008, Kazan, Russia aut Aminov L. MRS Laboratory, Kazan Federal University, Kremlevskaya 18, 420008, Kazan, Russia aut Kurkin I. MRS Laboratory, Kazan Federal University, Kremlevskaya 18, 420008, Kazan, Russia aut Pöppl A. Faculty of Physics and Earth Sciences, University of Leipzig, Linnéstr. 5, 04103, Leipzig, Germany aut Applied Magnetic Resonance Springer Vienna 46/7(2015-07-01), 741-748 0937-9347 46:7<741 2015 46 723 https://doi.org/10.1007/s00723-015-0676-1 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00723-015-0676-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Rakhmatullin R. MRS Laboratory, Kazan Federal University, Kremlevskaya 18, 420008, Kazan, Russia aut NATIONALLICENCE 700 1- Aminov L. MRS Laboratory, Kazan Federal University, Kremlevskaya 18, 420008, Kazan, Russia aut NATIONALLICENCE 700 1- Kurkin I. MRS Laboratory, Kazan Federal University, Kremlevskaya 18, 420008, Kazan, Russia aut NATIONALLICENCE 700 1- Pöppl A. Faculty of Physics and Earth Sciences, University of Leipzig, Linnéstr. 5, 04103, Leipzig, Germany aut NATIONALLICENCE 773 0- Applied Magnetic Resonance Springer Vienna 46/7(2015-07-01), 741-748 0937-9347 46:7<741 2015 46 723