Comparison study of the magnetic permeability and dc conductivity of Co–Ni–Li ferrite nanoparticles and their bulk counterparts

• Published in: Journal of magnetism and magnetic materials Vol. 354; pp. 1 - 6
• Main Authors: Assar, S.T., Abosheiasha, H.F., El Nimr, M.K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2014; Elsevier
• Subjects: Bulk sampling; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Curie temperature; dc Conductivity; Direct current; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in multilayers, nanoscale materials and structures; Exact sciences and technology; Ferrite; Magnetic permeability; Magnetic properties and materials; Magnetic properties of nanostructures; Nanocrystalline materials; Nanoparticle; Nanostructure; Permeability; Physics; Resistivity; Ferrite; Nanoparticle; Magnetic permeability; dc Conductivity; Curie temperature; Grain boundaries; Electrical conductivity; Curie point; Bond lengths; Ferrites; Nanoparticles; Temperature effects; Vibrational modes; Chemical composition; Porosity; Microstructure; Exchange interactions
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2013.10.029

The temperature dependence of relative permeability and dc electrical conductivity of nanosamples and their bulk counterparts of Co0.5Ni0.5−2xLixFe2+xO4 (from x=0.00 to 0.25 in step of 0.05) was investigated. The values of the relative permeability of the nano-samples are lower than their bulk counterparts as a result of porous and nano-grained structure besides the effect of the larger volume of grain boundaries in the nanosamples. Moreover, the dc conductivity of the nanosamples is higher than their bulk counterparts. This is probable explained according to the shorter metal–oxygen bonding length and higher lattice vibrations of the nanosamples. Also, the values of the relative permeability of both nano and bulk samples exhibit stability over a considerable range of temperatures. This may make them useful in practical applications that require stability. All the nanosamples show high rising Curie temperature values with increasing the Li content up to the sample of x=0.15 thereafter a decrease of the Curie temperature occurs while the inverse behavior was observed in their bulk counterparts. The interpretation of these findings is explained in the discussion. Moreover, in general doping Co–Ni ferrites with Li ions improves their electrical and magnetic properties and this is clearly observed in the nanosample of x=0.15 which can be regarded as the most promising sample for microwave applications. •The physical properties of both nano and bulk samples of Co–Ni–Li ferrites were investigated.•Permeability values of both nano and bulk samples show stability over a wide range of temperatures.•The relative permeability of the nanosamples is lower than their bulk counterparts.•The dc conductivity of the nanosamples is higher than their bulk counterparts.•The change of dc conductivity of both nano and bulk samples with Li content has the same behavior.