A review of reverse pulse plating techniques in the electrodeposition of magnetic alloys - Part 1

Magnetic materials always arouse interest due to their unique properties. Both soft and hard magnetic materials are exploited for energy harvesting application, magnetic recording and in MEMS. To boost the applicability of these materials, more versatile fabrication techniques must be developed. Even though the rare earth permanent magnets produced through powder metallurgy can guarantee the highest magnetic performance, this fabrication technique is not practical for the MEMS industry. Moreover, rare earths are very expensive elements. Electrodeposition seems a preferable alternative to chemical or physical vapour deposition techniques to produce both thin and thick magnetic deposits based on transition metal alloys. Among electrodeposition techniques, reverse pulse plating (RPP) guarantees improved mechanical properties and has been found to be beneficial for reducing internal stresses and modifying the internal microstructure and surface morphology as well as for producing thicker layers without observing cracks. Part 1 of the review focuses on how RPP can be used to tailor mechanical properties and morphology to achieve miniaturisation compared to other techniques, particularly in application fields that can benefit from it, such as the microelectronics industry. RPP also modifies magnetic properties by inducing changes in the microstructure. In Part 2 of this review, the state-of-the-art of hard and soft magnetic alloys deposited through RPP will be discussed, examining how this technique can tailor the crystalline structure to influence the coercivity of soft magnetic materials and the magnetic anisotropy of hard magnetic materials.