Giant Faraday rotation, magnetic and nonlinearity of diamagnetic glass tailored by plasmonic-magnetic bimetallic Au-Ni NPs

Glass containing plasmonic-magnetic nanoparticles have presented striking potential for plasmonic and nonlinear properties. For the first time, we report the synthesis and the magnetic/magneto-optical characterization of plasmonic-magnetic bimetallic Au-Ni nanoparticles (NPs) in heavy metal oxide diamagnetic glasses through co-sputtering technique. The optimum parameters for deposition, diffusion and formation of AuNi NPs were determined and< 50 nm AuNi NPs were synthesized in glass. Compositional and chemical valence states analysis revealed that the NPs is metallic AuNi, oxidization occurred for temperature high than 380 °C. The incorporation of Au-Ni NPs endowed the diamagnetic glass intense SPR peaks and superior optical nonlinearities comparable to that of host and single Au incorporated glasses. The alloy of transition metal Ni contributed to remarkable ferromagnetic character to glasses with characteristic M-H and M-T relations. Giant Verdet constant were obtained for glass and influential reasons were investigated insight of SPR effect, optical energy band gap and magnetization. Glass having 42 nm-AuNi NPs treated at 380 °C for 6 h exhibited huge Verdet constant of 72.66 rad/T m, large third-nonlinear susceptibility of 8.14 × 10 ⁻¹¹ esu and strong ferromagnetic moment. This glass will be promising for advanced optical nonlinear and magneto optical applications.