Magnetic studies of 0.7(Fe₂O₃)/0.3(ZnO) nanocomposites in nanopowder form and dispersed in polymer matrix

Magnetic properties of 0.7(Fe₂O₃)/0.3(ZnO) nanocomposite synthesized by traditional wet chemistry method and containing only two phases: ZnO (nonmagnetic) and ZnFe₂O₄ (magnetic, with nanocrystallites of average size 12 nm, but forming large agglomerates, up to 100 nm in size) were studied by DC magnetization and ferromagnetic resonance (FMR). The investigated nanocomposite was either in a form of nanopowder or dispersed at concentration of 0.1 wt.% in poly(ethylene naphthalate-block-tetramethylene oxide) PTMO-b-PEN polymer matrix. Similarities and differences in magnetic behavior of these two samples revealed by the study of static magnetization and FMR spectra have been discussed relative to different morphologies and the associated variation of interparticle interactions. Moreover, thermal and thermo-oxidative stability of the nanocomposite and the neat polymer have been studied by thermogravimetric method.