Mechanical properties of soft, electrodeposited Fe-Co-Ni films for magnetic recording heads

• Published in: IEEE transactions on magnetics Vol. 38; no. 5; pp. 2231 - 2233
• Main Authors: Xiaomin Liu, Feng Huang, Zangari, G., Weaver, M.L.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.09.2002; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Alloys; Annealing; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; FCC; Iron; Magnetic films; Magnetic heads; Magnetic materials; Magnetic properties and materials; Magnetic properties of monolayers and thin films; Magnetic properties of surface, thin films and multilayers; Magnetic recording; Magnetism; Mechanical factors; Physics; Soft magnetic materials; Stress measurement; Studies; Recording head; Ferromagnetic materials; Mechanical properties; Fe-Co-Ni thin films; Iron; Magnetic heads; XRD; Experimental study; Cobalt; Magnetic thin films; Thin films; Thin film devices; Electrodeposition; Nickel; magnetic recording heads
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2002.802678

Electrodeposited Fe-Co-Ni alloys are promising candidates for the writer in ultrahigh-density magnetic recording systems. In this paper, the mechanical properties of these materials have been studied by stress measurements as a function of temperature and nanoindentation. The alloy films (/spl sim/1-/spl mu/m-thick) were electrodeposited onto Cu/Ti/Si substrates. Three distinct structural regions were observed: FCC, mixed FCC+BCC, and BCC phases as Fe content in the alloy increased. The internal stress of Fe-Co-Ni films increases with decreasing current density, as reported for Ni-Fe films. The hardness of the as-deposited films was around 4.8 GPa; after annealing to 400/spl deg/C hardness was reduced to 3.6 GPa. The coefficient of thermal expansion CTE was /spl sim/10-11 /spl times/ 10-6/spl deg/C/sup -1/, comparable to typical values of bulk Ni/sub 78/Fe/sub 22/ (CTE -12 /spl times/ 10/sup -1//spl deg/C/sup -1/). Reduced Young's modulus E/(1 - /spl nu//sup 2/) changes from 150 to 180 Gpa, corresponding to the structural change from BCC to FCC. The ratio H/E is smaller than other materials investigated for write heads, indicating a lower resistance to deformation. H/E further decreases after annealing.