Magnetostrictive CoFe films were investigated for use as magnetoelastic tags or sensors. The ability to electrodeposit these films enables batch fabrication processes to pattern a variety of geometries while controlling the film stoichiometry and crystallography. Previous research developed a chemistry and plating parameters to maximize magnetostriction with a stoichiometry range of Co_0.7-0.75Fe_0.3-0.25and 20-30nm grain size. To further optimize the magnetostriction of electrodeposited CoFe films, the effect of the substrate was examined using copper, gold, and nickel electrodeposited base layers with varying preferred orientations and grain sizes. X-ray diffraction spectroscopy and electron backscatter diffraction were used to determine the crystal structure and crystallite size. Additionally, a hard magnet setup was used to apply a magnetic field during electrodeposition of the CoFe alloy to control the alignment of the magnetic domains. Magnetic force microscopy was used to determine the magnetic structure of the films as a function of the applied field’s magnitude and direction. Magnetic field and substrate effects were then correlated to magnetostriction performance.

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.