Carbon Nanotube Assisted Enhancement of the Magneto-Optical Kerr Signal in Nickel Thin Films

In this paper, the effect of carbon nanotubes (CNTs) acting as a covering layer on the [Glass/Ni] sample was experimentally investigated. To this end, a 48 nm thick Ni thin film was initially deposited on the glass substrate using a thermal evaporation method. Afterward, a spin-coating method was employed to deposit a thin layer of CNTs on the Ni thin film, thereby forming the [Glass/Ni/CNT] structure. Compared to [Glass/Ni] samples, the presence of CNTs led to 100% and 180% enhancement in the longitudinal Kerr signal of spin-coated samples. Field emission scanning electron microscopy, energy-dispersive x-ray spectroscopy, UV–Vis spectra and vibrating-sample magnetometer analyses were employed to characterize and investigate the morphology, elemental analysis, and optical and magnetic characteristics of the resulting structures. As a covering layer, the CNTs enhanced the absorption of light in the UV–visible wavelength range while also amplifying the interaction of light with the Ni layer without seriously changing other magnetic properties of the structure. Accordingly, using a simple approach, the Kerr signal was amplified more than three times compared to that of an uncovered sample, providing useful applications for magnetic sensors.