Multi-polarly micro rotor prepared from isotropic nano-crystalline films with self-bonding layer

A magnetized micro rotor such as 1.6 mm in outer diameter was prepared from a laminated isotropic nanocrystalline film with an optimized self-bonding layer. A relative density(RD) higher than 85 % in perpendicular direction of the above film could be obtained, and an estimated permeance coefficient, B/μoH, exceeded 20 by 3-D finite element method. Furthermore, an enhancement of magnetic torque and relative torque constant, dT/dH-gradient, of the above-mentioned sample with the single pole pair could be achieved. Consequently, it was found that use of laminated isotropic film with optimized self-bonding layer is effective in obtaining a multi-polarly magnetized micro rotor with highly dense torque compared with those of a bonded magnet prepared from consolidated flake with the same materials.