ISSN 0021-3640, JETP Letters, 2014, Vol. 99, No. 9, pp. 527–530. © Pleiades Publishing, Ltd., 2014. Original Russian Text © I.A. Yakovlev, S.N. Varnakov, B.A. Belyaev, S.M. Zharkov, M.S. Molokeev, I.A. Tarasov, S.G. Ovchinnikov, 2014, published in Pis’ma v Zhurnal Eksperimental’noi i Teoreticheskoi Fiziki, 2014, Vol. 99, No. 9, pp. 610–613. 527 1. Thin films of the Fe–Si system attract rather high interest of researchers owing to their unique physical properties and prospects of their application in spintronics devices [1–4]. In magnetic metals such as iron or permalloy, the degree of electron spin polar- ization is about 40–45%. It was already demonstrated that the high degree of spin polarization of electrons in silicon can be created by their injection from a ferro- magnetic metal electrode. The lower threshold of the spin polarization is 30% [5]. However, the possibility of the spin transfer decreases sharply due to the uncontrolled formation of different silicides on the interface of such structures [6, 7]. This problem can be solved by creating high-quality ferromagnetic Fe 3 Si silicide. According to calcula- tions, it is a ferromagnetic semimetal with the spin polarization at a level of 43% and rather high Curie temperature of 577°C [8]. The formation of the com- pletely epitaxial structure on the basis of silicon is of the highest interest. On one hand, this is due to the close- ness of the interplanar distances (111) of silicon and iron silicide for the epitaxial growth (d Si = 0.3138 nm (PDF 4+ card #00-005-0565), = 0.3271 nm (PDF 4+ card #04-015-3939), Si(111)||Fe 3 Si[111] [9]). On the other hand, a larger electron mean free path is expected in the single-crystal tunnel layers than in the polycrystalline structures. The main aim of this work was determining the technological conditions for the formation of ferro- magnetic Fe 3 Si silicide and finding the ferromagnetic resonance parameters. d Fe 3 Si 2. The Fe 3 Si structure was prepared by the method of thermal evaporation in superhigh vacuum on the boron-doped atomically pure substrate Si(111) (the resistivity of 5–10 Ω cm) on an Angara modernized molecular-beam epitaxy device [10]. The base vacuum in the technological chamber was 1.3 × 10 –8 Pa. The substrate was subjected to chemical treatment before synthesis with subsequent thermal annealing in super- high vacuum. The chemical treatment based on the technique proposed in [11] included three stages: the process of degreasing, the removal of the natural oxide from the Si substrate, and the formation of the passi- vating film of SiO 2 oxide with a thickness of ~1.5 nm on the Si surface. After the chemical treatment, the substrate was placed in superhigh vacuum, where it was subjected to the thermal annealing. In the process of thermal annealing, the Si(111) plate was heated gradually for 3 h to 650°C at a rate of 4°C per minute and exposed at this temperature for 15 min. The pressure in the chamber did not increase higher than 5.6 × 10 –7 Pa. Then, the substrate was heated sharply to 800°C with the exposure of 30 s. After that, the temperature was lowered again to 650°C. These “pulses” were performed until the addi- tional reflections from the reconstructed surface Si(111)7 × 7 appeared in the reflection high-energy electron diffraction pattern, which indicated the prep- aration of the atomically pure silicon surface. Then, the substrate temperature was lowered to 150°C and was preserved for 60 min prior to evaporation. Study of the Structural and Magnetic Characteristics of Epitaxial Fe 3 Si/Si(111) Films I. A. Yakovlev a, *, S. N. Varnakov a, b , B. A. Belyaev a–c , S. M. Zharkov a, c , M. S. Molokeev a , I. A. Tarasov a, b , and S. G. Ovchinnikov a–c a Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, 660036 Russia * e-mail: yia@iph.krasn.ru b Reshetnev Siberian State Aerospace University, Krasnoyarsk, 660014 Russia c Siberian Federal University, Krasnoyarsk, 660041 Russia Received March 28, 2014 The results of the structural and magnetic studies of the epitaxial structure prepared during the simultaneous evaporation from two iron and silicon sources on an atomically pure Si(111)7 × 7 surface at a substrate tem- perature of 150°C have been presented. The epitaxial structure has been identified as a single-crystal Fe 3 Si silicide film with the orientation Si[111]||Fe 3 Si[111] using methods of the X-ray structural analysis, transmis- sion electron microscopy, and reflection high-energy electron diffraction. It has been established that the epi- taxial Fe 3 Si film at room temperature has magnetic uniaxial anisotropy (H a = 26 Oe) and a relatively narrow uniform ferromagnetic resonance line (ΔH = 11.57 Oe) measured at a pump frequency of 2.274 GHz. DOI: 10.1134/S0021364014090124