Interdiffusion in Heusler film epitaxy on GaAs (001)

Description

Ferromagnetic layers with a high spin polarization on semiconductor substrates are attracting increasing interest for applications in spin- and magnetoelectronics. A promising material class are the binary or ternary Heusler compounds that include also so-called halfmetallic ferromagnets, e. g., Co2FeSi. For attaining high spin polarization perfect crystallographic order as well as the formation of abrupt and chemically defined interfaces are essential. According to recent theory, spin-transport across interfaces depends dramatically on the type of atoms participating in the contact layer with detrimental consequences of interface disorder due to interdiffusion or interface reactions. The talk focuses on on interdiffusion processes occurring during molecular beam epitaxy of the binary, thus experimentally simpler FeSi films on GaAs(001), including the Heusler compound Fe3Si. Our experiments reveal a strong interdiffusion of Fe and Si into the GaAs substrate as well as of As and Ga into the FeSi films, creating intermixed layers of 2–3 nm thickness in both, film and substrate. Interdiffusion is dominant already at moderate growth temperatures required for crystallographic ordering, thus demanding new concepts including appropriate diffusion barriers for the development for ferromagnet/semiconductor hybrid systems.

Period	16 Nov 2010
Event title	unbekannt/unknown
Event type	Other
Location	AustriaShow on map