LAUSR

Abstract Light provides a potential approach to modulate magnetism due to the low energy consumption, which could be used for the development of optical-magnetic coupling devices, data storage technology and quantum computation technology. In this work, NiFe2O4 nanocrystals with inverse spinel structure confined in non-magnetic Al2O3 film are synthesized. Based on theoretical calculation and experimental validation, it is revealed that the NiFe2O4 nanocrystals experience compressive strain from Al2O3 film. The compressive strain can be partially relaxed, leading to the formation of disorder layers at the surfaces of strained NiFe2O4 nanocrystals, which provide an ideal platform to modulate magnetism optically. A remarkable light-modulated ferromagnetism in the strained NiFe2O4 nanocrystals is observed. This work demonstrates a novel approach to optically engineer the ferromagnetic properties for applications in next generation of magnetic nano-devices.