Like a balloon, peculiar magnet grows and shrinks
Alloy of iron and gallium increases volume in a magnetic field
![magnet](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/05/ag_magnet_free.jpg?fit=860%2C460&ssl=1)
STRETCHY MAGNET Layers of roughly 40-micrometer-long magnetic cells inside an iron-gallium alloy, seen in this micrograph, enable the material to expand and contract in a magnetic field.
Courtesy of H. Chopra