Structural and magnetic properties of magnetron sputtered Co70Fe30 films on GaAs(110)

The surface morphology, crystal structure, and in-plane magnetic anisotropy of sputter deposited Co(70)Fe(30) films on GaAs(110) epilayer substrates have been investigated. The surface morphology of thin Co(70)Fe(30) 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 Co(70)Fe(30)(110) is present in our films, although we cannot unambiguously deconvolute characteristic reflections of Co(70)Fe(30)(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 Co(70)Fe(30) film is coherently matched to the GaAs(110) substrate. The magnetic anisotropies in both 35 and 1100 angstrom 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 Co(x)Fe((100-x))/GaAs(110). This work shows that sputter deposition may be used to produce structurally coherent bcc-Co(70)Fe(30)/GaAs(110) contacts suitable for spin-injection applications. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3093875]