Light-Modulated Ferromagnetism Of Strained NiFe₂O₄ Nanocrystals

In recent years,due to the unique physical and chemical properties of the composite nanocrystalline particles,it has attracted the attention of many scholars.In this paper,firstly,it is prepared by pulsed laser deposition?PLD?technique,and then NiFe2O4 nanocrystalline particles are determined by Raman spectroscopy,transmission electron microscopy,XPS and other characterization methods,and then tested by PPMS?Comprehensive Physical Measurement System?.The magnetic properties and the magnetic properties when no light applied have found excellent magnetic properties.Light provides a potential approach to modulate the 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 surface of strained NiFe₂O₄nanocrystals 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.