Some clues about the interphase reaction between ZnO and MnO2 oxides |
| |
Authors: | F. Rubio-Marcos,A. Quesada,M.A. Garcí a,M.A. Bañ ares,M.S. Martí n-Gonzalez,J.F. Ferná ndez |
| |
Affiliation: | a Instituto de Cerámica y Vidrio, CSIC, 28049 Madrid, Spain b Instituto de Magnetismo Aplicado (ADIF-UCM-CSIC), Madrid, Spain c Insituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain d Departamento de Física de Materiales, UCM, 28040 Madrid, Spain e Instituto de Catálisis y Petroleoquímica, CSIC, Madrid 28049, Spain f Instituto de Microelectrónica de Madrid, CSIC, Tres Cantos, Madrid 28760, Spain |
| |
Abstract: | Raman spectroscopy is used to evidence both the nature of the interphase reaction between ZnO and MnO2 particles and its kinetic evolution. Zn cations migrate from the ZnO grains during oxygen vacancies formation process and diffuse into the MnO2 particles leading to an interphase region with an intermediate valence Mn+3-O-Mn+4. Large amounts of desorbed Zn cations promote the formation of ZnMn2O4 structure, in addition to the intermediate valence state. The system evolves towards complete formation of the spinel phase at higher thermal treatment times. The reactivity of the ZnO plays an important role in the formation of this interphase. Low-reactivity ZnO powder, in which the oxygen vacancies are previously produced, shows a stabilization of the intermediate valence state with very limited formation of the spinel phase. A clear correlation between the amount of the intermediate state interphase and the magnetic properties has been established. |
| |
Keywords: | ZnO-MnO2 system Binary oxides Interphase diffusion Raman spectroscopy Magnetic properties |
本文献已被 ScienceDirect 等数据库收录! |
|