I have used Nitinol as a shape memory material for a small experiment that requires change of shape ( curved to straight or small to longer) to be controlled. These materials change shape due to external temperature variation. Now I am looking for some materials that will change shape with applied electric or magnetic field. Is there anything practically usable? Heard about magnetic memory alloys. Can anyone help me to point me a micrometer length wire to change its length or shape upon external field variation?