Electrodeposition and characterization of CoNiMnP permanent magnet arrays for MEMS sensors and actuators

In this paper, electroplated CoNiMnP permanent magnet arrays have been designed, fabricated and studied. The arrays contain cylinder magnets with various radius as well as cubic magnets with different aspect ratio. It was observed that the retentivity and the energy density of cylinder arrays decreased as radius increased. For cubic arrays, the retentivity and the energy density enhanced with the increase of the aspect ratio. Moreover, the effects of the array thickness on the magnetic performance were also investigated. It was found that, for cubic arrays, both the retentivity and the energy density dropped with thickness increasing. But the total energy stored in the square shape array was rose up to 180%. A high coercivity of 751 Oe, a retentivity up to 8887Gs and an energy density of 17.4 kJ/m3 were successfully obtained in cubic arrays. By modifying the geometry of the arrays, the retentivity and the energy density can be improved up to 115% and 129%, respectively. It is utilized in the fabrication of novel electromagnetic energy harvester successfully.