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Nonequilibrium and spintronics effects in superconducting structures / Majed Abdelsalam Nashaat Moharram Abdelghani ; Supervised Tharwat Elsherbini , Yu . M. Shukrinov , Ali Yehia Ellithi

By: Contributor(s): Material type: TextTextLanguage: English Publication details: Cairo : Majed Abdelsalam Nashaat Moharram Abdel ghani , 2020Description: 210 P . : charts ; 25cmOther title:
  • تأثيرات عدم الاتزان و دوران الالكترونات المغزلى فى البنيات فائقة التوصيل [Added title page title]
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Dissertation note: Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Physics Summary: The aim of this thesis is to characterize the properties of nonequilibrium and spin-ironies effects in several superconducting structures.If electron population in su-perconductors is driven out of thermal equilibrium, various nonequilibrium effects can take place either as a steady-state dynamic equilibrium or as a time-dependent regime. In the first part of this thesis, we investigate non-stationary and stationary charge imbalance effect in layered superconducting structures which form a system of coupled Josephson junctions. Precise numerical study is done for the current-voltage (IV-) characteristics of capacitively coupled Josephson junctions under external ra-diation. The effect of charge imbalance is observed on the Shapiro step.The Shapiro step shows a finite slope and shift from the canonical value v {u2014} h/2ete, where m is the frequency of the external radiation. The shift and elope values depend on the relaxation time of the quasi-particles and the thickness of the superconducting layer. Moreover, we can find the relaxation time of the quasi-particles from the slope of the Shapiro step. As for the second part of the thesis, we investigate the spintronic effects in several superconducting Josephson junctions coupled to ferromagnet. By now it is well-known that current-phase relation in Josephson junctions coupled to term-magnet is strongly sensitive to the mutual orientation of the magnetizations in the F-layer. In these junctions mutual coupling between magnetization and Josephson phase takes place. This coupling between the Josephson and magnetic subsystems leads to the supercurrent induced magnetization dynamics. We study the manifes-tation of different types of coupling between magnetization and Josephson phase on the appearance of subharmonic steps which forms the devil's staircase structure
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Thesis Thesis قاعة الرسائل الجامعية - الدور الاول المكتبة المركزبة الجديدة - جامعة القاهرة Cai01.12.20.Ph.D.2020.Ma.N (Browse shelf(Opens below)) Not for loan 01010110081259000
CD - Rom CD - Rom مخـــزن الرســائل الجـــامعية - البدروم المكتبة المركزبة الجديدة - جامعة القاهرة Cai01.12.20.Ph.D.2020.Ma.N (Browse shelf(Opens below)) 81259.CD Not for loan 01020110081259000

Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Physics

The aim of this thesis is to characterize the properties of nonequilibrium and spin-ironies effects in several superconducting structures.If electron population in su-perconductors is driven out of thermal equilibrium, various nonequilibrium effects can take place either as a steady-state dynamic equilibrium or as a time-dependent regime. In the first part of this thesis, we investigate non-stationary and stationary charge imbalance effect in layered superconducting structures which form a system of coupled Josephson junctions. Precise numerical study is done for the current-voltage (IV-) characteristics of capacitively coupled Josephson junctions under external ra-diation. The effect of charge imbalance is observed on the Shapiro step.The Shapiro step shows a finite slope and shift from the canonical value v {u2014} h/2ete, where m is the frequency of the external radiation. The shift and elope values depend on the relaxation time of the quasi-particles and the thickness of the superconducting layer. Moreover, we can find the relaxation time of the quasi-particles from the slope of the Shapiro step. As for the second part of the thesis, we investigate the spintronic effects in several superconducting Josephson junctions coupled to ferromagnet. By now it is well-known that current-phase relation in Josephson junctions coupled to term-magnet is strongly sensitive to the mutual orientation of the magnetizations in the F-layer. In these junctions mutual coupling between magnetization and Josephson phase takes place. This coupling between the Josephson and magnetic subsystems leads to the supercurrent induced magnetization dynamics. We study the manifes-tation of different types of coupling between magnetization and Josephson phase on the appearance of subharmonic steps which forms the devil's staircase structure

Issued also as CD

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