STUDY OF PARTIALLY STABILIZED CE DOPED ZRO2 CRYSTALS BY ELECTRON PARAMAGNETIC RESONANCE

Autor: V. V. Osiko, V. A. Shustov, I. V. Yatsyk, R. M. Eremina, V. A. Myzina, M. A. Borik, I. I. Fazlizhanov, Elena E. Lomonova
Rok vydání: 2018
Předmět:
Zdroj: Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering. 20:32-37
ISSN: 2413-6387
1609-3577
DOI: 10.17073/1609-3577-2017-1-32-37
Popis: The study of crystals of ZrO2 solid solutions (PSZ) stabilized with yttrium and cerium oxides was carried out by electron paramagnetic resonance (EPR) in the X and Q range. The presence of Zr3+ centers in annealed ZrO2 crystals stabilized only by yttrium oxide (2.8 mol.% Y2O3) is established. Another kind of paramagnetic O−centers appear when CeO2 is added to ZrO2 crystals in addition to yttrium oxide. To estimate the concentration of Ce3+ ions in PZS crystals, EPR spectra were recorded in the presence of a reference specimen at 7 K. Paramagnetic Ce3+ ions have been identified and their relative amounts in PSZ crystals before and after high−temperature heat treatment has been measured. The annealing in air leads to a decrease in the concentration of Ce3+ ions for all compositions and changes the color of the crystals from red to white. After annealing in the 2.0Y0.8Ce3Zr sample, the amount of paramagnetic Ce3+ ions decreased approximately twice. Paramagnetic centers from Ce3+ are not detected in a the sample with a low cerium content of 0.1 mol.% after annealing which indicates the complete transition of Ce3+ to the Ce4+ state. It is shown that the formed paramagnetic centers of cerium are bound by strong exchange interactions. No angular dependence of the EPR lines for the paramagnetic Ce3+ cations on the applied external magnetic field was observed. The probable reason for the absence of such angular dependence is that impurity rare−earth ions are located next to each other, forming impurity clusters with effective spin Seff = 1/2.
Databáze: OpenAIRE
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