Magnetic property, Mössbauer spectroscopy and microwave reflection loss of maghemite nanoparticles (γ-Fe2O3) encapsulated in carbon nanotubes

Nanoparticles of maghemite (γ-Fe2O3) were prepared from FeCl3 by using a reduction method using hydrazine hydrate as reducing agent. The prepared nanoparticles were incorporated in non-magnetic matrix of multi-walled carbon nanotubes (CNTs). The crystallographic phases of γ-Fe2O3 and γ-Fe2O3-CNT were confirmed by using X-ray diffractograms (XRD), high resolution transmission electron microscopy (HRTEM) and Mössbauer spectroscopy. The nanoparticles of γ-Fe2O3 were incorporated in CNTs. Dynamic magnetic properties of the samples were characterized at room temperature (RT) and static magnetic properties were measured from RT down to 5 K by using SQUID magnetometer which confirmed the presence of superparamagnetic (SPM) relaxation of the nanoparticles. High value reflection losses of the sample over (X and Ku bands) were observed, which would be suitable for applications in microwave devices.