Mechanical metamaterials, man-made structures that exhibit unique behaviors not easily observed in nature, have attracted a lot of concerns and have been widely studied in the past three decades. However, most of the current developed mechanical metamaterials are difficult to be tuned by external mechanical loadings due to the immutable building blocks, and are limited for future application.

In this research, we will present some kind of magnetic metamaterials designs, comprising hard-magnetic microparticles deliberately embedded in soft materials. Both experiment and finite element method are taken to analyze the influence of magnetization directions and external magnetic fields on the buckling and deformation of such metamaterials. In comparison with the mechanical induced deformations, the deformations of our magnetic metamaterials caused by uniform magnetic fields are found to be more fruitful and robust to be tuned, and the topology of domain walls in such metamaterials can be effectively controlled by varying the magnetization directions. Furthermore, the above magnetic-induced deformations can significantly alter the elastic waves propagating in such structures. The combination of magnetic and mechanical actuations imparts great tunable properties to metamaterials, which may open avenues to the creation of programmable mechanical metamaterials.