Si/Fe flux ratio influence on growth and physical properties of polycrystalline β-FeSi2 thin films on Si(100) surface
Tarasov, I. A.
Visotin, M. A.
Alexandrovsky, A. S.
Kosyrev, N. N.
Yakovlev, I. A.
Molokeev, M. S.
Lukyanenko, A. V.
Krylov, A. S.
Fedorov, A. S.
Varnakov, S. N.
Ovchinnikov, S. G.
Институт инженерной физики и радиоэлектроники
Кафедра теоретической физики и волновых явлений
Journal Name:Journal of Magnetism and Magnetic Materials
Journal Quartile in Scopus:Q1
Journal Quartile in Web of Science:Q2
Bibliographic Citation:Tarasov, I. A. Si/Fe flux ratio influence on growth and physical properties of polycrystalline β-FeSi2 thin films on Si(100) surface [Текст] / I. A. Tarasov, M. A. Visotin, A. S. Alexandrovsky, N. N. Kosyrev, I. A. Yakovlev, M. S. Molokeev, A. V. Lukyanenko, A. S. Krylov, A. S. Fedorov, S. N. Varnakov, S. G. Ovchinnikov // Journal of Magnetism and Magnetic Materials. — 2017. — № 440. — С. 144-152
This work investigates the Si/Fe flux ratio (2 and 0.34) influence on growth of β-FeSi2 polycrystalline thin films on Si(100) substrate at 630 ˚C. Lattice deformation for the films obtained are confirmed by X-ray diffraction analysis (XRD). The volume unit cell deviation from that of β-FeSi2 single crystal are 1.99 % and 1.1 % for Si/Fe = 2 and Si/Fe = 0.34, respectively. Absorption measurements show that the indirect transition (~ 0.813 eV) of the Si/Fe = 2 sample changes to the direct transition with a bandgap value of ~0.806 eV for the sample prepared at Si/Fe = 0.34. Along with this direct transition, the absorption spectra exhibit an additional feature with an excitation energy of ~0.56 eV. Surface magneto-optic Kerr effect (SMOKE) measurements detect ferromagnetic behavior of the β-FeSi2 polycrystalline films grown at Si/Fe = 0.34 at T=10 K, but no ferromagnetism was observed in the samples grown at Si/Fe = 2. Theoretical calculations refute that the cell deformation can cause the emergence of magnetization and argue that the origin of the ferromagnetism, as well as the lower impurity direct transition, is β-FeSi2 stoichiometry deviations. Raman spectroscopy measurements evidence that the film obtained at Si/Fe flux ratio equal to 0.34 has the better crystallinity than the Si/Fe = 2 sample