Important role of the non-uniform Fe distribution for the ferromagnetism in group-IV-based ferromagnetic semiconductor GeFe

Journal Article · Fri Nov 07 00:00:00 EST 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4901060· OSTI ID:22308209

Wakabayashi, Yuki K.; Ohya, Shinobu; Ban, Yoshisuke; Tanaka, Masaaki ^[1]

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1. Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

We investigate the growth-temperature dependence of the properties of the group-IV-based ferromagnetic semiconductor Ge{sub 1−x}Fe{sub x} films (x = 6.5% and 10.5%), and reveal the correlation of the magnetic properties with the lattice constant, Curie temperature (T{sub C}), non-uniformity of Fe atoms, stacking-fault defects, and Fe-atom locations. While T{sub C} strongly depends on the growth temperature, we find a universal relationship between T{sub C} and the lattice constant, which does not depend on the Fe content x. By using the spatially resolved transmission-electron diffractions combined with the energy-dispersive X-ray spectroscopy, we find that the density of the stacking-fault defects and the non-uniformity of the Fe concentration are correlated with T{sub C}. Meanwhile, by using the channeling Rutherford backscattering and particle-induced X-ray emission measurements, we clarify that about 15% of the Fe atoms exist on the tetrahedral interstitial sites in the Ge{sub 0.935}Fe{sub 0.065} lattice and that the substitutional Fe concentration is not correlated with T{sub C}. Considering these results, we conclude that the non-uniformity of the Fe concentration plays an important role in determining the ferromagnetic properties of GeFe.

• OSTI ID: 22308209
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 17; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRYSTAL DEFECTS
CRYSTAL GROWTH
CURIE POINT
ELECTRON DIFFRACTION
EMISSION
FERROMAGNETISM
FILMS
GERMANIUM ALLOYS
IRON ALLOYS
LATTICE PARAMETERS
MAGNETIC PROPERTIES
MAGNETIC SEMICONDUCTORS
RUTHERFORD BACKSCATTERING SPECTROSCOPY
SPATIAL DISTRIBUTION
STACKING FAULTS
TEMPERATURE DEPENDENCE
X RADIATION
X-RAY SPECTROSCOPY