INFLUENCE OF THE SUBSTRATE ON MAGNETIC PROPERTIES OF ELECTRODEPOSITED Co-Pt PERMANENT MICROMAGNET ARRAYS FOR MEMS APPLICATIONS

摘要

We have successfully fabricated arrays of cylindrical Co-Pt micromagnets with 2 μm diameter by optical lithography and electrodeposition. The influence of the substrate (Cu(100) and Cu(111)), current density (CD = 10-30 mA/cm~2) and cylinder aspect ratio (AR = 0.0275-0.11) on the magnetic properties have been investigated. It has been found that the Cu(111) substrate provides better properties at high CD and low AR, such as: intrinsic coercivity (_MH_C) up to 4.3 kOe, retentivity (B_r) up to 6.9 kG and large energy product (BH)_(max) up to 5.38 MGOe (42.83 kJ/m~3). Current density has a small influence on the magnetic properties of cylinders with high AR. On the contrary, an increase in CD from 10 to 30 mA/cm~2 induces a relevant improvement in the magnetic properties of cylinders with small AR. The large energy product achieved and the compatibility with CMOS fabrication, render these structures interesting candidates for hard magnetic components in microelectromechanical systems.