Laser-micromachined Permanent Magnet Arrays with Spatially Alternating Magnetic Field Distribution

Many MEMS systems can benefit from dense, alternating arrays of permanent magnets (PM) with high energy-product and substantial magnetic flux density adjacent to the array. In this work, we demonstrate laser machining fabrication and assembly techniques to create linear PM alternating arrays with periods as low as 230 μm. Comb-shaped magnet structures are micromachined from a 300 μm thick samarium cobalt (SmCo) substrate using an IR laser. These structures are then magnetized and assembled in an interlocking fashion to make alternating magnet arrays of various total lengths. Scanning Hall-effect sensor measurements taken 80 μm above the surface indicate sinusoidally varying magnetic fields with periods as expected from the underlying magnet geometry and peak magnetic flux density amplitudes of 0.1 T.