Si/Fe flux ratio influence on growth and physical properties of polycrystalline β-FeSi2 thin films on Si(100) surface

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:440

Article; Proceedings Paper

Tarasov, I. A.^1,2  Visotin, M. A.^2,3  Aleksandrovsky, A. S.^2,3  Kosyrev, N. N.²  Yakovlev, I. A.^1,2  Molokeev, M. S.^2,4  Lukyanenko, A. V.^2,3  Krylov, A. S.²  Fedorov, A. S.^2,4  Varnakov, S. N.^1,2  Ovchinnikov, S. G.^1,2,3 

[1] Siberian State Aerosp Univ, 31 Krasnoyarsky Rabochiy Ave, Krasnoyarsk 660014, Russia

[2] RAS, SB, KSC, Kirensky Inst Phys,Fed Res Ctr, Akad Gorodok 50,Bld 38, Krasnoyarsk 660036, Russia

[3] Siberian Fed Univ, Inst Engn Phys & Radioelect, Krasnoyarsk 660041, Russia

[4] Far Eastern State Transport Univ, Seryshev Str 47, Khabarovsk 680021, Russia

关键词: beta-FeSi2 iron disilicide;    Optical properties;    Reflection high-energy electron diffraction;    Raman spectroscopy;    ab initio calculation;   

DOI  :  10.1016/j.jmmm.2016.12.084

来源: Elsevier

【 摘 要 】

This work investigates the Si/Fe flux ratio (2 and 0.34) influence on the growth of beta-FeSi2 polycrystalline thin films on Si(100) substrate at 630 degrees C. Lattice deformations for the films obtained are confirmed by X-ray diffraction analysis (XRD). The volume unit cell deviation from that of beta-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 (similar to 0.704 eV) of the Si/Fe = 0.34 sample changes to the direct transition with a bandgap value of similar to 0.816 eV for the sample prepared at Si/Fe = 2. The absorption spectrum of the Si/Fe = 0.34 sample exhibits an additional peak located below the bandgap energy value with the absorption maximum of similar to 0.36 eV. Surface magneto-optic Kerr effect (SMOKE) measurements detect the ferromagnetic behavior of the beta-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 absorption peak, is beta-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.

【 授权许可】

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