Epitaxial Growth and Magnetic Properties of Ferromagnetic Semiconductor Ge1-xFex Thin Films Epitaxially Grown on Si(001) Substrates

Ferromagnetic semiconductor Ge1-xFex thin films were grown on Si(001) substrates by low-temperature molecular beam epitaxy. The crystal structure of the Ge1-xFex films was of diamond type for 0≤x≤17.5%, and their lattice constant monotonically decreased with increasing Fe content x. No precipitations of any other Fe–Ge phase were detected in structural characterizations. Magnetic circular dichroism (MCD) characterizations revealed that the origin of the ferromagnetic ordering in the Ge1-xFex films comes from the diamond-type semiconductor phase. The anomalous Hall effect was clearly observed and their ferromagnetic behavior was consistent with the results of the MCD observations. As the Fe content increased, the resistivity of the film monotonically decreased, and simultaneously, the Curie temperature monotonically increased. All the experimental results indicate that the Ge1-xFex films grown on Si(001) have the properties of intrinsic ferromagnetic semiconductor.

[1]  S. Sugahara,et al.  A spin metal–oxide–semiconductor field-effect transistor using half-metallic-ferromagnet contacts for the source and drain , 2004 .

[2]  Clustering in a precipitate-free GeMn magnetic semiconductor. , 2006, Physical review letters.

[3]  Masaaki Tanaka,et al.  Magnetic properties of heavily Mn-doped quaternary alloy ferromagnetic semiconductor (InGaMn)As grown on InP , 2003 .

[4]  Epitaxial growth of the diluted magnetic semiconductors CryGe1−y and CryMnxGe1−x−y , 2003, cond-mat/0302231.

[5]  Carrier-induced ferromagnetism in Ge(Mn,Fe) magnetic semiconductor thin-film structures , 2006 .

[6]  Masaaki Tanaka,et al.  Spin MOSFETs as a basis for spintronics , 2006, TOS.

[7]  Masaaki Tanaka,et al.  Magneto-optic effect of the ferromagnetic diluted magnetic semiconductor Ga1−xMnxAs , 1998 .

[8]  S. Sugahara,et al.  Magneto-optical properties of group-IV ferromagnetic semiconductor Ge1−xFex grown by low-temperature molecular beam epitaxy , 2005 .

[9]  Satoshi Sugahara,et al.  Precipitation of amorphous ferromagnetic semiconductor phase in epitaxially grown Mn-doped Ge thin films , 2005 .

[10]  J. E. Mattson,et al.  A Group-IV Ferromagnetic Semiconductor: MnxGe1−x , 2002, Science.

[11]  Y. Shuto,et al.  Structural and magnetic properties of epitaxially grown Ge1−xFex thin films: Fe concentration dependence , 2007 .

[12]  H. Ohno,et al.  Zener model description of ferromagnetism in zinc-blende magnetic semiconductors , 2000, Science.

[13]  H. Ohno,et al.  Hole-mediated ferromagnetism in tetrahedrally coordinated semiconductors , 2000, cond-mat/0007190.

[14]  Satoshi Sugahara,et al.  A spin metal-oxide-semiconductor field-effect transistor (spin MOSFET) with a ferromagnetic semiconductor for the channel , 2005 .

[15]  Y S Chu,et al.  Novel germanium-based magnetic semiconductors. , 2003, Physical review letters.

[16]  James R. Thompson,et al.  Ferromagnetic percolation in MnxGe1−x dilute magnetic semiconductor , 2005 .

[17]  H. Ohno,et al.  Transport properties and origin of ferromagnetism in (Ga,Mn)As , 1998 .

[18]  Y. Shuto,et al.  Epitaxial growth and magnetic properties of a new group-IV ferromagnetic semiconductor : Ge1- xFex , 2006 .

[19]  B. Jonker,et al.  Growth of ferromagnetic nanoparticles in Ge:Fe thin films , 2005 .

[20]  O.M.J. van 't Erve,et al.  Comparison of Fe/Schottky and Fe/Al2O3 tunnel barrier contacts for electrical spin injection into GaAs , 2004 .

[21]  M. Tanaka,et al.  MOS-Based Spin Devices for Reconfigurable Logic , 2007, IEEE Transactions on Electron Devices.

[22]  M. Sawicki,et al.  Prospects for high temperature ferromagnetism in (Ga,Mn)As semiconductors , 2005 .

[23]  A. Marty,et al.  High-Curie-temperature ferromagnetism in self-organized Ge1−xMnx nanocolumns , 2006, Nature materials.

[24]  K. Ando,et al.  Magneto-optical study of spin-carrier interactions in (In,Mn)As , 2004 .

[25]  G. Schmidt,et al.  Fundamental obstacle for electrical spin injection from a ferromagnetic metal into a diffusive semiconductor , 1999, cond-mat/9911014.

[26]  T. Vallaitis,et al.  Structural and magnetic properties of Mn5Ge3 clusters in a dilute magnetic germanium matrix , 2006 .

[27]  S. Sugahara,et al.  Spin metal-oxide-semiconductor field-effect transistors (spin MOSFETs) for integrated spin electronics , 2005 .