Title of Paper:Oxygen-exposure mediated electron transfer and d(0) ferromagnetism in metal oxide nanocrystals system

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Affiliation of Author(s):航天学院

Journal:JOURNAL OF ALLOYS AND COMPOUNDS

Key Words:CeO2 Nanocrytals Defect Ferromagnetism

Abstract:The room temperature d(0) ferromagnetism origin is still highly controversial in oxide systems, due to the lack of subtle experimental set-up as well as sensitive defect detection. Herein, we developed O-rich treatments on Ceria nanocrystals, H2O2 and O-2 ambient exposure, which creates intrinsic O defects without introducing trace level of impurities or changing crystallinity. Interestingly, results found that significant oxygen adsorption along with distinct augment of RT ferromagnetism were observed after both H2O2 treatment and O-2 ambient exposure. The more the oxygen molecule adsorbed, the stronger the ferromagnetism was. Furthermore, Electron Spin Resonance (EPR) results illustrate that the Ce3+ concentration experienced reverse variation in H2O2 treated-and O-2 exposed-samples, thus excluding the possibility of Ce cation as the cause of the ferromagnetism. Similar magnetism enhancements were also observed in La2O3, ZrO2 and SrTiO3 nanocrystals after H2O2 treatment. Based on these results, we surmise that the interstitial oxygen, rather than the other sources, facilitated the electron transfer and the dilute ferromagnetism of CeO2. This work established a general model in clarifying the origin of the disputed ferromagnetism in metal oxide system. (C) 2017 Elsevier B.V. All rights reserved.

ISSN No.:0925-8388

Translation or Not:no

Date of Publication:2017-10-15

Co-author:fmh,Liu, Yuan

Correspondence Author:lvjinpeng