Search

The surface morphology, crystal structure, and in-plane magnetic anisotropy of sputter deposited Co70Fe30 films on GaAs(110) epilayer substrates have been investigated. The surface morphology of thin Co70Fe30 films appears to closely follow that of the underlying GaAs(110) substrate. The study of the crystal structure by x-ray diffraction shows that no crystallographic orientation other than Co70Fe30(110) is present in our films, although we cannot unambiguously deconvolute characteristic reflections of Co70Fe30(110) from those of GaAs(110) due to the very small lattice mismatch. High-resolution transmission electron microscopy shows that the crystal structure of the Co70Fe30 film is coherently matched to the GaAs(110) substrate. The magnetic anisotropies in both 35 and 1100 Å thick films are consistent with those of similar epitaxial films, and demonstrate that a strong bcc (110) texture is propagated throughout the entire film thickness. The cubic and uniaxial anisotropy constants extracted by fitting with the Stoner–Wohlfarth model are consistent with those of molecular beam epitaxy grown bcc CoxFe(100-x)/GaAs(110). This work shows that sputter deposition may be used to produce structurally coherent bcc-Co70Fe30/GaAs(110) contacts suitable for spin-injection applications. [ABSTRACT FROM AUTHOR]

The in-plane magnetic properties of Co0.7Fe0.3 films sputtered onto Al0.1Ga0.9As and Al0.1Ga0.9As/GaAs epilayers are consistent with a strongly oriented bcc crystal structure with clean metal-semiconductor interfaces. However, the interface induced uniaxial magnetic anisotropy is oriented along one of the in-plane <100>, rather than <110>, as is the case in molecular beam epitaxy—grown films. Resonant x-ray measurements show interfacial magnetic disorder in films on Al0.1Ga0.9As, which accounts for the difference in magnetic anisotropy behavior between samples on Al0.1Ga0.9As and Al0.1Ga0.9As/GaAs epilayer substrates, and which may have significant consequences for the spin-injection efficiency across such interfaces. [ABSTRACT FROM AUTHOR]