Microstructure and Magnetic Behavior of Fe/Ti Multilayered Films

<jats:title>ABSTRACT</jats:title><jats:p>Fe/Ti multilayered films composed of Fe and Ti layers with various thickness ( d<jats:sub>Fe</jats:sub> of 10 ∼ 1000 A and d<jats:sub>Ti</jats:sub> of 10 ∼ 200 A ) have been prepared at Ar gas pressure of 2 mTorr by two pairs of Facing Targets Sputtering apparatus which can deposit very thin and continuous films on plasma-free substrates. The total thickness of Fe layers was 1000 A in all of the specimen films.</jats:p><jats:p>The periodic microstructure due to compositional modulation was clearly observed not only in the low angle region of X-ray diffraction diagrams but also in the Auger electron spectroscopic depth profile.</jats:p><jats:p>With decreasing d<jats:sub>Fe</jats:sub> from 1000 to 20 A, the diffraction intensity of (110) plane in the Fe bcc phase lowered for d<jats:sub>Ti</jats:sub> of 10∼200 A and its interplanar spacing ( d-spacing ) increased for d<jats:sub>Ti</jats:sub> above 50A. This diffraction peak disappeared with further decreasing d below 15 A. At d<jats:sub>Fe</jats:sub> around 25 A, a different peak appeared at the angle slightly lower than that of Fe(110) peak. The diffraction intensity of (002) plane in the Ti hcp phase increased with decreasing d<jats:sub>Fe</jats:sub>. However, its d-spacing depended little on the d<jats:sub>Fe</jats:sub> and took the same value as that of bulk Ti except for very small d<jats:sub>Ti</jats:sub>.</jats:p><jats:p>The net saturation magnetization of Fe layers in all of the specimen films decreased gradually with decreasing d<jats:sub>Fe</jats:sub> from 1000 to 50 A, decreased abruptly with further decreasing d<jats:sub>Fe</jats:sub> and became nearly zero at d<jats:sub>Fe</jats:sub> below 15A.</jats:p><jats:p>The films annealed at 200 and 400 °C showed obscure periodic microstructure and had larger d-spacing of ∝ −Fe(110) and smaller saturation magnetization than those of the as-deposited ones.</jats:p>