Figure 15. Head-assisted magnetic reprogramming strategies for hard-magnetic soft materials.

(a) Magnetic materials with low Curie temperature (above which the material loses its remanent magnetization) can be easily demagnetized upon global heating or localized laser heating above the Curie point and then remagnetized by an externally applied magnetic field during cooling.²¹⁵ (b) Hard-magnetic particles encapsulated in phase-change materials with low melting temperature can temporarily move and rotate when heated above the melting point to reorient themselves along the applied field during the heating process. Upon cooling, the reoriented particles are immobilized within the solidified phase-change material to yield a newly programmed magnetization direction in the composite.^216,217