Effect of Substrate Temperature on the Ordered Phase Formation in Sm–Ni Thin Film Deposited on Cu(111) Underlayer

Abstract

Sm <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">17</sub> Ni <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">83</sub> (at.%) alloy thin films are prepared on Cu underlayers hetero-epitaxially grown on MgO(111) single-crystal substrates by employing an ultra-high vacuum molecular beam epitaxy system. The substrate temperature is varied from 100 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C to 500 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C. The film growth behavior and the detailed resulting film structure are respectively investigated by in situ reflection high-energy electron diffraction and by a combination of out-of-plane and in-plane X-ray diffractions. With increasing the temperature up to 300 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C, formation of ordered SmNi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> phase is recognized. The films deposited above 400 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C consist of only epitaxial SmNi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> (0001) crystal, whereas the films deposited below the temperature include amorphous phase and/or a hexagonal ordered phase other than SmNi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> . When the temperature is increased from 300 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C to 500 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C, the long-range order degree of SmNi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> film increases from 0.60 to 0.97. SmNi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> phase formation is enhanced with increasing the temperature.