Synthesis of Nd-Fe-B/Fe hybrid micro-magnets

Abstract

There is an overgrowing interest in the synthesis of high performance micro magnets due to their wide application areas in MEMS, microfluidics, and micro-robotics. In addition, they possess great potential to become a model system for the development of next-generation hard magnets. In this study, NdFeB/Fe hybrid micro-magnets have been synthesized by a photolithography technique. NdFeB micro and Fe nano powders in the form of nano-thin flakes have been synthesized by one step surfactant assisted planetary ball milling. The fabricated nano-thin flakes with different lateral sizes have been obtained by varying the milling time. Room temperature coercivities of up to 3.1 kOe for NdFeB has been achieved after milling for 8 h. Photoresist and powders of NdFeB and Fe have been mixed at various powder-to-resist ratios. SU-8 has been chosen as the photoresist due to its resistance to chemicals and its suitability to be utilized in MEMS technology. Micro islands of SU-8/NdFeB/Fe have been prepared according to the manufacturer's recommendations for pure SU-8. The hybrid micromagnets in pillar form have been successfully produced. The evolution of magnetic, structural and microstructural properties of these micro magnets will be reported. Successful fabrication of hybrid micro-magnets using the methodology prescribed in this work can pave the way for the development of next-generation MEMS.