Novel ratios of silver iron nanoparticles with the chemical formulas Ag2Fe2O4 with Ag/Fe ratio = 1/1 and Ag0.5Fe2.5O4 with Ag/Fe ratio = 1/5 were successfully synthesized using a flash auto-combustion technique at 400 oC. Structural properties were studied using XRD (X-ray diffraction), AFM (Atomic Force Microscopy), FESEM (Field Emission Scanning Electron Microscopy), and FTIR (Fourier transform infrared) analyses. The nanosize range determined from XRD analysis lies in 56.6-71.1 nm for Ag0.5Fe2.5O4 and Ag2Fe2O4 nanoparticles. The morphology was analyzed using AFM and FESEM to confirm that the particle size of both samples was spherical and nanosized with agglomeration. Fourier transform infrared (FTIR) analysis was performed to confirm nano-samples' formation. Both samples were measured using a vibrating sample magnetometer to study their magnetism. By increasing the concentration of iron ions, the saturation magnetization (Ms) increased 5-fold for Ag0.5Fe2.5O4 nanoparticles compared with Ag2Fe2O4 nanoparticles. Moreover, there is a relation between saturation magnetization and antimicrobial activity, in which high (Ms) gives high antibacterial activity. Thus, Ag0.5Fe2.5O4 had a high (Ms) and high efficacy against the tested bacteria. However, Ag2Fe2O4 showed high activity against Candida albicans. Moreover, a high-frequency application was measured from the magnetic measurements, showing that both samples could be applied at a very high frequency (VHF) in the radio wave range. Finally, both samples could be antibacterial materials, particularly Ag0.5Fe2.5O4 nanoparticles. However, Ag2Fe2O4 nanoparticles are strongly recommended for antifungal activity against Candida albicans.