Epitaxial ferromagnetic metal/GaAs(100) heterostructures

Ferromagnetic bcc-FexCo1-x(100) films have been successfully grown on GaAs( 100) and ScyEr1-yAs(100) by molecular beam epitaxy. X-ray diffraction combi ned with reflection high energy electron diffraction and low energy electro n diffraction patterns revealed the epitaxial orientation of bcc-FexCo1-x(1 00)< 010 >parallel to GaAs(100)< 010 > and bcc-FexCo1-x(100) < 010 >paralle l to ScyEr1-yAs(100)< 010 >. Rutherford backscattering channeling minimum y ields, chi(min)similar to 3%, suggest epitaxial films of high crystalline q uality. Vibrating sample magnetometry measurements show in-plane uniaxial a nisotropy and fourfold in-plane anisotropy for FexCo1-x grown on GaAs(100) and ScyEr1-yAs(100), respectively. The difference in magnetic anisotropy is interpreted as arising from the ScyEr1-yAs interlayer altering the surface symmetry from twofold symmetry for GaAs(100) to fourfold symmetry. Misorie nted substrates were also used to increase the step density in the [011] di rection, which induced an additional uniaxial anisotropy with a [011] easy axis and a [01 (1) over bar] hard axis. This step structure symmetry-induce d magnetic anisotropy generated a split field similar to 50 Oe in the hard axis for bcc-FexCo1-x(100) grown on ScyEr1-yAs(100) surfaces. (C) 2000 Amer ican Vacuum Society. [S0734-211X(00)07104-3].