Formation of Negative Ions on the Surface of a Solid Body and Their Influence on the Thermoelectronic and Autoelectronic Emission of Free Electrons
Leonid Ivanovich Gretchikhin
Issue:
Volume 5, Issue 3, September 2019
Pages:
47-55
Received:
29 August 2019
Accepted:
19 September 2019
Published:
14 October 2019
Abstract: On the surface of the main crystal, positive ions interact with a negative cloud of free electrons and turn into neutral atoms. Neutral atoms having affinity to the electron other than zero additionally capture the electron and become negative ions. It is shown that under the action of ponderomotive forces the crystal surface is noticeably deformed, and it is experimentally confirmed. Besides, it is experimentally proved that three-atomic molecules possess allotropy in distribution of the built-in electric moments. The analysis of different physical models, which describe the thermo-and auto-electric emission of free electrons, is carried out and their inconsistency is shown. Thermal electron and field emission arise due to the temperature population of negative ions on the crystal surface and cluster vibrations in the near-surface layer. Field emission is thermal electron emission from negative ions and the Fermi level, which is transformed due to the action of the external electric field on the work of the surface by ponderomotive forces.
Abstract: On the surface of the main crystal, positive ions interact with a negative cloud of free electrons and turn into neutral atoms. Neutral atoms having affinity to the electron other than zero additionally capture the electron and become negative ions. It is shown that under the action of ponderomotive forces the crystal surface is noticeably deformed...
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A Theoretical Approach: Effects of Mn Substitution in Cobalt Ferrite
Md. Ziaul Ahsan,
Md. Aminul Islam
Issue:
Volume 5, Issue 3, September 2019
Pages:
56-61
Received:
25 July 2019
Accepted:
13 August 2019
Published:
4 November 2019
Abstract: This paper reports on the effect of Mn substitution in cobalt ferrite to explore the probable correlation among the structural, magnetic, and magneto-mechanical properties by a theoretical approach. Three compositions of Mn doped Cobalt ferrites at different Mn concentration (x) = 0.125, 0.25, 0.375, 0.5 have been undertaken for their analytical study to understand the correlation among the aforesaid properties. In this approach, an empirical equation has been formulated based on idealistic cation distribution in tetrahedral and octahedral sites of cobalt ferrite at room temperature. The hopping lengths and bond lengths have also been estimated using the corresponding Stanley’s equations in idealistic condition. The estimated lattice constant is found to decrease and effective magnetic moment μferri to increase with the Mn content, substituted for Co in the octahedral site due to increased A-B interactions. This increasing effect of Mn content in cobalt ferrite may be significant to the tunability of the Curie temperature, TC and may have an influence on superparamagnetism (SPM). On the other hand, the compositions where Mn substituted for Fe may increase the porosity due to their increased bond lengths with Mn content and thus may optimize them for applications in the environmental (gas) sensors. However, the analysis of the predicted effects of Mn and correlation thereon is completely based on the theoretical approach and thereby need experimental verification to confirm and supplement them.
Abstract: This paper reports on the effect of Mn substitution in cobalt ferrite to explore the probable correlation among the structural, magnetic, and magneto-mechanical properties by a theoretical approach. Three compositions of Mn doped Cobalt ferrites at different Mn concentration (x) = 0.125, 0.25, 0.375, 0.5 have been undertaken for their analytical st...
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