Metastable Sm(Fe,Cu)5 ordered alloy films formed on Cu(111) underlayers
Faculty of Science and Engineering, Chuo University,
1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
2 Graduate School of Fine Arts, Tokyo University of the Arts, 12-8 Ueno-koen, Taito-ku, Tokyo, 110-8714, Japan
Sm-Fe thin films are prepared on Cu(111) underlayers hetero-epitaxially grown on MgO(111) single-crystal substrates by using an ultra-high vacuum molecular beam epitaxy system. The Sm/Fe composition is varied from Fe-rich (10 at. % Sm - Fe) to Sm-rich (30 at. % Sm - Fe) region including SmFe5 stoichiometry. The influence of film composition on the film structure is studied by in-situ reflection highenergy electron diffraction and X-ray diffraction. Metastable Sm(Fe,Cu)5 ordered phase formation is recognized in the Sm-Fe films with the investigated compositions. Cu atoms diffuse from the underlayer into the Sm-Fe film and substitute the Fe site in SmFe5 structure forming an alloy compound of Sm(Fe,Cu)5. The Sm-Fe films with Fe-rich compositions consist of Sm(Fe,Cu)5 and bcc-Fe phases, whereas the Sm-Fe films with Sm-rich compositions consist of Sm(Fe,Cu)5 and amorphous phases. Cu atom diffusion into Sm-Fe film is assisting the formation of ordered phase.
© Owned by the authors, published by EDP Sciences, 2013