| abstract |
The present invention concerns nano-ferrite materials (in powder form) made from a mixture of rare earths, transition metals and light rare earth elements. Nano-ferrites (nanoparticles and nanorods) of Nd 1-x MexFe2O4 (Me = Co, Ni, Mn, Sn, etc.) spinel ferrites have been prepared by the co-precipitation method. XRD X-ray diffraction and TEM imagery confirm the proper crystallisation of the nanorods in the case of NdFe2O4 doped with transition metals and nanoparticles in the case of NdFe2O4 doped with light rare earth elements. The results show that the cation distribution on the tetrahedral and octahedral sites in the spinel network is partially inverse. The magnetic properties of the samples have been characterised by using a superconductor quantum interference device (SQUID). The magnetic properties show that the system has a high moment of saturation and a moderate coercive force at room temperature. The residual magnetisation, saturation magnetisation, coercive force, blocking temperature, and transition temperature of the nano-ferrite material are optimised by the concentration of the magnetic ions, the size and the shape of the nanoparticles in order to achieve the characteristics required for well-defined applications. The superparamagnetic nanoparticles created are multifunctional materials of which the size and shape can be used for the exchange of magnetism and other uses. The value of such nano-ferrites is in providing a major advancement in terms of understanding and controlling the phase, composition and size thereof, in relation to the basic magnetic response. Said oxide nanoparticles made from a mixture of transition metals and rare earths are simple and economical to produce in high quantities with uniform magnetic properties and can be encapsulated, functionalised or left bare as an oxide which is stable at room temperature. |