Precipitation of amorphous ferromagnetic semiconductor phase in epitaxially grown Mn-doped Ge thin films

Abstract

We investigated the origin of ferromagnetism in epitaxially grown Mn-doped Ge thin films. Using low-temperature molecular beam epitaxy, Mn-doped Ge films were successfully grown without precipitation of ferromagnetic Ge-Mn intermetallic compounds, such as Mn5Ge3. Magnetic circular dichroism measurements revealed that the epitaxially grown Mn-doped Ge films exhibited clear ferromagnetic behavior, but the Zeeman splitting observed at the critical points was not induced by the s,p-d exchange interactions. High-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy analyses show phase separation of amorphous Ge1-xMnx clusters with high Mn content from a Mn-free monocrystalline Ge matrix. Since amorphous Ge1-xMnx was characterized as a homogeneous ferromagnetic semiconductor, the precipitation of the amorphous Ge1-xMnx clusters is the origin of the ferromagnetic semiconductor behavior of the epitaxially grown Mn-doped Ge films.

arXiv comment12pages, 4figures

References in corpus (2)

• First principles investigation of transition-metal doped group-IV semiconductors: R${}_x$Y${}_{1-x}$ (R=Cr, Mn, Fe; Y=Si, Ge)
• Spin-polarized current amplification and spin injection in magnetic bipolar transistors

Cited by in corpus (5)

• Spinodal nanodecomposition in magnetically doped semiconductors
• Structure and magnetism of self-organized Ge(1-x)Mn(x) nano-columns
• Spin-glass-like behavior of Ge:Mn
• Magneto-optical properties of a new group-IV ferromagnetic semiconductor Ge1-xFex grown by low-temperature molecular beam epitaxy
• Strain and correlation of self-organized Ge_(1-x)Mn_x nanocolumns embedded in Ge (001)