Assessment of Laser-Induced Damage in Laser-Micromachined Rare-Earth Permanent Magnets

The effects of micromachining bulk rare-earth magnets are investigated by measurements of the moment of sub-millimeter scale micromachined structures. A model representing these effects is also presented to provide a basis for interpreting the results. Laser-induced damage to the magnetic material, manifesting as a loss of magnetic properties, is estimated to reach 10–20 $\mu$ m from the magnet edge in the lateral dimension. The results indicate the affected volume due to laser micromachining bulk rare-earth magnets is limited to less than 25 $\mu$ m, laterally through the material, for the rare-earth magnetic materials tested.