High frequency study of core-shell reusable CoFe2O 4-ZnO nanospheres


Recently, coated nanoshells combined with magnetic nanoparticles and cancer-cell-specific antibodies have been used to develop a multifunctional platform for simultaneously diagnosing and treating cancer, via magnetic resonance imaging and photothermal therapy. For this application, core-shell nano-spheres with a low resonance frequency (low GHz range) in a strong applied field are required. In this aspect, ferromagnetic resonance experiment is an important tool for determining the dynamic properties of nano-materials. Magnetic field dependence of resonance frequency (fr) and linewidths (Δ and ΔH) for both the ZnO coated and uncoated CoFe 2O4 hollow spheres are studied using a vector network analyzer. As compared to uncoated CoFe2O4 hollow sphere, ZnO coated CoFe2O4 showed reduced resonance frequency, larger Δ and ΔH, reduced gyromagnetic ratio and effective fields. The experimental results are confirmed with the effective medium theory. © 2014 AIP Publishing LLC.

Publication Title

Journal of Applied Physics