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10XV International Symposium on Self-Propagating High-Temperature Synthesis
THERMITE SYNTHESIS OF NANOCOMPOSITE Co-In2O3 AND Fe-In2O3 FILMS
L. E. Bykova*", V. G. Myagkov", V. S. Zhigalov", and A. A. Matsynin"
aKirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036 Russia *e-mail: lebyk@iph.krasn.ru
DOI: 10.24411/9999-0014A-2019-10027
Granular nanocomposites consisting of ferromagnetic nanoparticles embedded in semiconductor (In2O3, TiO2, ZnO, and SnO2) or dielectric (SiO2, Al2O3, MgO, and ZrO2) matrices have been intensively studied as objects interesting both for fundamental research and application. The most common methods for synthesizing magnetic nanocomposites and hybrid materials use wet chemistry; these include sol-gel methods, solvothermal methods, sonochemical synthesis, thermal decomposition, chemical reduction, and radiolysis [1, 2]. After wet chemistry, the next most important method of obtaining functional magnetic nanocomposites is the formation of magnetic granular films created from a joint deposition of metal and an insulator [3, 4]. The search for new methods to create ferromagnetic nanocomposite films is relevant. This paper discusses the synthesis of ferromagnetic nanocomposite film materials on the basis of solid-state thermite reactions between layers of oxides of 3d metals (Co3O4 and Fe2O3) and the metal In. Ferromagnetic nanocomposite Co-In2O3 thin films were synthesized using thermite reactions between layers of In and Co3O4 (1) by vacuum annealing of In/Co3O4 film bilayers.
3CosO4 +8In = 4In2O3 + 9Co (Tin ~ 190°C)
(1)
Ferromagnetic nanocomposite Fe-In2O3 thin films were synthesized using thermite reactions between layers of In and Fe2O3 (2) by vacuum annealing of In/Fe2O3 film bilayers.
P (a)
Fe2O3 + 2In = In2O3 + 2Fe (Tin ~ 180°C)
(2)
=3 : (b) /U
03 / I
w
c
50 100 150 200 250
Position (nm)
1 |jm
Fig. 1. (a) Electron microscopy image and (b) elemental composition of the Co-In2O3 nanocomposite film.
_SI IS 2019_Moscow, Russia
The initiation temperature of reactions (Tin) and the structural and magnetic properties of the nanocomposite films were identified. Electron-microscopic study of films showed the creation of Co, Fe (60-100 nm) nanoclusters surrounded by a layer of M2O3 over a large area (Figs. 1, 2). Thus, the termite method is promising for synthesizing ferromagnetic nanocomposite thin films consisting of ferromagnetic clusters embedded in oxide matrices and characterized by the high magnetization and chemical stability.
Position (nm)
Fig. 2. (a) Electron microscopy image and (b) elemental composition of the Fe-In2O3 nanocomposite film.
The research was supported by RFBR together with the Government of the Krasnoyarsk
Territory, the Krasnoyarsk Regional Fund of Science (project
no. 18-42-243009r_mol_a).
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