Room temperature ferromagnetism and giant permittivity in chemical   routed Co1.5Fe1.5O4 ferrite particles and their composite with NaNO3
  We report structural, magnetic and dielectric properties of Co1.5Fe1.5O4 nanoparticles and their composites with non-magnetic NaNO3. The samples were derived from metal nitrates solution at different pH values. The chemical routed sample was air heated at 200 0C and 500 0C. Heating of the material showed unusual decrease of crystallite size, but cubic spinel structure is seen in all samples. The samples of Co1.5Fe1.5O4 showed substantially large room temperature ferromagnetic moment, electrical conductivity, dielectric constant, and low dielectric loss. The samples are soft ferromagnet and electrically highly polarized. The interfaces of grains and grain boundaries are actively participating to determine the magnetic and dielectric properties of the ferrite grains. The effects of interfacial contribution are better realized using the ferrite and NaNO3 composite samples. We have examined different scopes of modifying the magnetic and dielectric parameters using same material in pure and composite form. 
R.N. Bhowmik, P. Lokeswara Rao, and J. Udaya Bhanu
cond-mat.mtrl-sci