Amorphization of PrDy-FeCo-B microwire surface under nanosecond laser pulse

Abstract

Micromagnets used in robotic mechanisms, actuators, electromotive devices, micro-engines require protection from chemically destructive factors. Improving micromagnets in the NdFeB family is particularly important. We found that laser-stimulated amorphization of the surface of PrDy-FeCo-B microwires can restore the amorphous structure from polycrystalline microwires under a single laser irradiation pulse of 1 mJ power and 120 ns duration, penetrating to a depth of 1 μm. The thermal exchange in the microwire causes rapid cooling of the laser-irradiated area. We imprinted periodic local magnetic labels of ∼10 μm in length using single laser pulse. Initially crystalline (PrDy)2(FeCo)14B1 microwires were locally transformed to an amorphous phase by laser irradiation. The alternating amorphous magnetic patterns are magnetized perpendicular to the microwire’s main axis.