Si/Fe flux ratio influence on growth and physical properties of polycrystalline β-FeSi2 thin films on Si(100) surface
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Автор:
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.
Коллективный автор:
Институт инженерной физики и радиоэлектроники
Кафедра теоретической физики и волновых явлений
Дата:
2017-10Журнал:
Journal of Magnetism and Magnetic MaterialsКвартиль журнала в Scopus:
Q1Квартиль журнала в Web of Science:
Q2Библиографическое описание:
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. 144-152Аннотация:
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