Structural and magnetic properties of thin epitaxial Fe films on (110) GaAs prepared by metalorganic chemical vapor deposition

Abstract Iron films have been grown on (1 1 0) GaAs substrates by atmospheric pressure metalorganic chemical vapor deposition at substrate temperatures ( T s ) between 135°C and 400°C. X-ray diffraction (XRD) analysis showed that the Fe films grown at T s between 200°C and 330°C were single crystals. Amorphous films were observed at T s below 200°C and it was not possible to deposit films at T s above 330°C. The full-width at half-maximum of the rocking curves showed that crystalline qualities were improved at T s above 270°C. Single crystalline Fe films grown at different substrate temperature showed different structural behaviors in XRD measurements. Iron films grown at T s between 200°C and 300°C showed bulk α-Fe like behavior regardless of film thickness (100–6400 A). Meanwhile, Fe films grown at 330°C (144 and 300 A) showed a biaxially compressed strain between substrate and epilayer, resulting in an expanded inter-planar spacing along the growth direction. Magnetization measurements showed that Fe films (>200 A) grown at 280°C and 330°C were ferromagnetic with the in-plane easy axis along the [1 1 0] direction. For the thinner Fe films (⩽200 A) regardless of growth temperature, square loops along the [1 0 0] easy axis were very weak and broad.