Nano/Femtosecond laser processing in developing nanocrystalline functional materials for multi-core orthogonal fluxgate sensor

Abstract

In developing magnetic sensing elements, the sensitivity of magnetic sensors have been found to increase exponentially when multi-core structures are used as sensing elements. In this project, multi-core structured functional magnetic materials of extremely high permeability have been successfully developed with either nanosecond or femtosecond lasers. Methods such as nanosecond laser drilling of polymeric templates for electrodeposition of nanocrystalline nickel-iron wires and femtosecond laser machining of Vitrovac 6025X and nickel-iron thin films are investigated. Both methods are found to be suitable. For stacked laser-drilled templates, the best aspect ratio achieved for electroplated Ni-Fe wires is 1:50 with composition at 83% and 17%, respectively. For the second method using femtosecond laser on Vitrovac 6025X foils and electron-beam evaporated Ni-Fe thin films, the results showed that femtosecond laser processing can be used to fabricate the sensors. In addition, experiments show that laser irradiation can modify magnetic material to become softer.