A bi-stable vertical magnetic actuator with non-contact latching based on magnetic microlamination technology

Abstract

We present the design, fabrication and testing of a bi-stable vertical magnetic actuator which exhibits non-contact latching behavior that is enabled by magnetic microlamination technology. The lamination technology translates the structural periodicity (i.e. the multilayers of alternating magnetic and nonmagnetic materials) into magnetic-field-pattern periodicity, which in turn results in multi-stable energy states of the microsystem and leads to the defined latching behavior. A single-mask process is utilized to reduce the fabrication complexity of this actuator. The actuator has bi-stable vertical latching positions 40 μm-apart and the latching mechanism is solely based on magnetostatic interaction without the need for a mechanical stop. Input energies as low as 0.6 mJ for switching up and 0.02 mJ for switching down are needed to fulfill one full period of the bi-stable actuation. No external energy is needed in the latching positions. The behavior of the actuator is explained in terms of the energy landscape theory. These types of vertical multi-stable actuators could have potential applications as valves in micro-fluidic controls, or as integral parts of micro-mirrors in optical applications.

A bi-stable mechanism actuated by patterned permanent magnet and Cu-Ni integrated micro-coil

“…Therefore, the whole fabrication process needed multiple steps and was complicated. In 2018, Li et al [25] designed a permalloy (Ni 80 Fe 20 ) spring which acted both as FM and coil. The permalloy was movable and had a tendency to latch in alignment with a pair of fixed pre-magnetized FM to realize bi-stable states.…”