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Laser induced adjustment of the conductivity of rare earth doped Mn-Zn nanoferrite

El-Dek S. I., Ahmed M. A., Eltawil A. A., Afify M. S.

Materials Science Poland

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2017

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Vol. 35, No. 3

519--527

EN

Two series of Mn-Zn nanoferrites (namely Mn1-xZnxFe2O4 and Mn1-xZnxFe2-yRyO4) were synthesized using standard ceramic technique. X-ray diffraction and FT-IR were employed in the chacterization of the nanopowder. The X-ray density for each sample increased after laser irradiation which was correlated with the decrease in the unit cell volume. The study involved the thermal and frequency variation of the dielectric constant and AC conductivity of the investigated samples before and after laser irradiation. The later altered the conductivity by decreasing its value for the rare earth doped samples except for the Sm3+ doped one. The results suggested the exploitation of Mn-Zn doped rare earth nanoferrites in many technological applications demanding high resistivity.

2

Hybrid fixed point theorems in symmetric spaces via common limit range property

Imdad M., Chauhan S., Soliman A. H., Ahmed M. A.

Demonstratio Mathematica

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2014

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Vol. 47, nr 4

949--962

EN

In this paper, we point out that some recent results of Vijaywar et al. (Coincidence and common fixed point theorems for hybrid contractions in symmetric spaces, Demonstratio Math. 45 (2012), 611–620) are not true in their present form. With a view to prove corrected and improved versions of such results, we introduce the notion of common limit range property for a hybrid pair of mappings and utilize the same to obtain some coincidence and fixed point results for mappings defined on an arbitrary set with values in symmetric (semi-metric) spaces. Our results improve, generalize and extend some results of the existing literature especially due to Imdad et al., Javid and Imdad, Vijaywar et al. and some others. Some illustrative examples to highlight the realized improvements are also furnished.

3

Common fixed point theorems for set-valued and single-valued mappings

Ahmed M. A.

Demonstratio Mathematica

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2003

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Vol. 36, nr 2

471--481

EN

The concepts of δ-compatibility and weakly compatibility between a set-valued mapping and a single-valued mapping of Jungck and Rhoades [8, 9] are used to prove some common fixed point theorems on metric spaces. Generalizations of known results are thereby obtained. In particular, theorems by Fisher [2] and Khan, Kubiaczyk and Sessa [11] are generalized. An example is given to support our generalization.