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Mazen S.A.,Magnetic Semiconductor Laboratory | Taher A.M.E.,Magnetic Semiconductor Laboratory
Journal of Alloys and Compounds | Year: 2010

The mixed ferrite Cu1+x Six Fe2-2x O4; with 0 ≤ x ≤ 0.3 in step of 0.05 were prepared by standard ceramic techniques. The X-ray analysis confirmed that the compositions are well formed in a single phase. The d.c. and a.c. electrical conductivity as a function of temperature have been studied. The relation ln σ vs. T-1 showed two regions with different slopes for all values of x except x = 0.0 showed one slope only. The two activation energies around a kink point called Tk were calculated. The change of the slope at Tk was attributed to a change in the nature of type of conduction mechanism (i.e. from n-type to p-type). The activation energies were greater than 0.3 eV; which clearly suggested that the conduction is due to small polaron model. © 2010 Elsevier B.V. All rights reserved.

Mazen S.A.,Magnetic Semiconductor Laboratory | Abu-Elsaad N.I.,Magnetic Semiconductor Laboratory
Journal of Magnetism and Magnetic Materials | Year: 2010

Two series of mixed copper ferrites, Cu1+x Gex Fe2-2x O4 and Cu1+x Six Fe2-2x O4, have been analogously investigated for x=0.0, 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3. The two systems were prepared using the standard ceramic techniques. X-ray diffraction analysis indicates that both systems formed in a single phase cubic spinel structure. The lattice parameter has a constant value (0.838 nm±0.001) for the two series. The grain diameter was estimated from the scanning electron microscope micrographs for the two series. Some magnetic properties were measured at room temperature. The magnetization M was measured in the range of magnetizing field up to 5500 Am-1. The relative permeability (μr) was calculated from the B-H relation. The B-H loops were measured at constant magnetizing current (I=2.5 A which is equivalent to 900 Am-1). Also, the hystersis area and the magnetic parameters Br, Bs, mR (Br/Bs) and apparent energy loss (E) were estimated from the B-H loops; μr, Br, Bs and E are composition dependent. © 2009 Elsevier B.V. All rights reserved.

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