Structure, Magnetic Properties, and Phase Transformations in Electrodeposited Fe-Rich Fe-Pt Films

• Published in: IEEE transactions on magnetics Vol. 51; no. 7; pp. 1 - 9
• Main Authors: Defu Liang, Siyuan Ge, Zangari, Giovanni
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-07-2015; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Annealing; Coercive force; Coercivity; Cube texture; Iron; Magnetic confinement; Magnetic recording; Magnetism; Perpendicular magnetic anisotropy; Phase transformations; Surface layer; Texture; Transformations; magnetic hardening; Fe-Pt; phase transformation; magnetic films
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2015.2394326

Fe rich Fe-Pt films with 56 at.%-75 at.% Fe are electrodeposited from an alkaline solution. A face-centered cubic (111) texture is clearly observed for as-deposited films with <;62 at.% Fe, while a body centered cubic (110) orientation is seen for higher Fe fraction. After annealing in forming gas for 1 h at or above 400 °C, a transformation to a face centered tetragonal (FCT) L1_{0} phase was observed below 62 Fe at.%. With increasing Fe content, the annealed films show a texture change from (200) to (002); films with <;72% Fe show coercivity \sim 7 kOe while films with Fe above that value show small coercivity. Of particular interest are the 75 at.% films; these show a FCT structure after annealing at or above 450 °C, which differs from the L1_{0} structure and is characterized by low anisotropy; in contrast, a relatively high out of plane coercivity (1-3 kOe) is observed in 75 at.% films in the as-deposited or annealed conditions up to 350 °C.