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

Satoshi Sugahara·Kok Leong Lee·Shinsuke Yada·Masaaki Tanaka
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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.

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Satoshi Sugahara, Kok Leong Lee, Shinsuke Yada, Masaaki Tanaka. 2005-11-15. Precipitation of amorphous ferromagnetic semiconductor phase in epitaxially grown Mn-doped Ge thin films. https://doi.org/10.1143/jjap.44.l1426

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