Co-Pt micromagnets by electrodeposition

Arrays of cylindrical Co–Pt micromagnets with 2 μm diameter have been successfully fabricated by optical lithography and electrodeposition. The influence of applied current density and the aspect ratio on the magnetic properties of the micromagnets have been investigated. Intrinsic coercivities (MHc) up to 3.7 kOe, retentivities (Br) up to 4.9 kG, and large energy products (BH)max up to 34 kJ/m3 (4.31 MGOe) have been achieved. The cylinder aspect ratio strongly influences the magnetic properties of the magnet array. Specifically, coercivity MHc, squareness (Mr/Ms), and energy product (BH)max, all increase with increasing aspect ratio. Current density only slightly influences the magnetic properties. The large energy product attained and the compatibility with complementary metal–oxide–semiconductor fabrication, render these structures interesting candidates for hard magnetic components in microelectromechanical systems.