Inherently magnetic hydrogel for data storage based on the magneto-optical Kerr effect.

In this data explosion age, a large amount of data is generated every day. Such a fast data growth has aroused great interest in the field of data storage. Conventional data storage materials are mainly composed of hard and brittle materials but they may break in the case of mechanical operations, causing irreversible data loss. In this work, efforts have been devoted to fabricating a flexible and stretchable double network hydrogel for data storage based on the magneto-optical Kerr effect. The hydrogel possesses a storage modulus of over 10 Pa and remains unbroken under a strain of 3000%. The surface of the hydrogel is patterned with diamagnetic parts and paramagnetic parts alternately. When placed under a magnetic field, the surface of the hydrogel reflects the incident laser beam and changes the polarization plane of the reflected light. The outstanding flexibility and inherent magnetic properties of this hydrogel lay the groundwork for data storage and guarantee data safety.