Magnetic shape memory alloys display a key property crucial for many of their interesting functionalities: the extraordinarily high mobility of martensite twin boundaries. This mobility enables shape changes and many other effects under a magnetic field. However, the underlying reasons for this high mobility are still a puzzling mystery in the field.
Understanding this mobility begins with exploring the boundary structure across various length scales. The lecture will discuss the complex hierarchical twin microstructure around the twin boundary, and the roleof laminated twin structures and nanotwins in enhancing twin boundary mobility. Additionally, it will briefly address issues related to the lower length scale, specifically the crystal structure of individual twin domains.