Transition waves in Tristable Magnetoelastic Lattice*

We study the dynamics of phase transition in multistable magnetoelastic lattice. The unit cell consists of uniformly magnetized spherical magnets, leading to a tristable energy landscape for the onsite potential. The switching between multiple stable equilibria gives rise to a nonlinear wave called the transition wave. These dynamic phase boundaries travel within the structure with some unique characteristics. We report the existence of multiple types of transition waves emerging due to the asymmetric tristable energy landscape. We formulate an explicit energy transport equation that links the wave velocity to the asymmetric energy landscape and damping factors for such systems. We then analyze the collision of two similar transition waves that nucleate a new phase and transform the lattice to a new configuration. When two dissimilar transition waves collide, we observe the creation of a domain wall. We confirm the simulated predictions with an experimental demonstration. These results indicate the richness of dynamical phenomena in multistable lattices and could find applications in soft robotics, remote actuation, and reconfigurable structures.