Enhancement of magneto-optical Kerr response by LSPR in magneto plasmonic nanostructures for biological sensors

In this paper, design and fabrication of Glass/Ni/Au nanoparticles (NPs)/ZnS magneto-plasmonic nanostructure have been investigated in order to develop biological sensors. The Au NPs were synthesized by a co-precipitation method, and a vapor deposition technique was used to fabricate the multi-layer nanostructure. The longitudinal Kerr signal (LKS) of nanostructure has been measured and tried to be enhanced, thereby improving sensitivity. The results show that adding the Au NPs surrounded by ZnS layer on Ni magnetic thin film leads to an increase in the Kerr signal up to 84% without altering the magnetic properties significantly. In fact, the LKS of Glass/Ni/ZnS has increased due to the localized surface plasmon resonance (LSPR) by Au NPs in the interface of Ni/ZnS, thus increasing light interaction with both the dielectric layer and magnetic layer.