Design of dual-magnet memory machines

The memory machine, which adopts the aluminum-nickel-cobalt (AlNiCo) as the permanent magnet (PM) material, has attracted a wide attention. In this paper, by incorporating two kinds of PM materials including the neodymium-iron-boron (NdFeB) and the AlNiCo, the dual-magnet memory machine is proposed, which has more distinguished merits than its single-magnet counterpart. Due to the high coercivity of the NdFeB, the overall power density is augmented notably. Also, the risk of accidental demagnetization is significantly reduced. Most importantly, the design on how to combine these two kinds of PMs is discussed in detail, with emphasis on their shape, thickness and relative position. Both simulation and experimentation are given to illustrate the validity of the proposed design.