Nonequilibrium and spintronics effects in superconducting structures /
Majed Abdelsalam Nashaat Moharram Abdeghani
Nonequilibrium and spintronics effects in superconducting structures / تأثيرات عدم الاتزان و دوران الالكترونات المغزلى فى البنيات فائقة التوصيل Majed Abdelsalam Nashaat Moharram Abdelghani ; Supervised Tharwat Elsherbini , Yu . M. Shukrinov , Ali Yehia Ellithi - Cairo : Majed Abdelsalam Nashaat Moharram Abdel ghani , 2020 - 210 P . : charts ; 25cm
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 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
Nonequilibrium Spintronics Superconducting structures
Nonequilibrium and spintronics effects in superconducting structures / تأثيرات عدم الاتزان و دوران الالكترونات المغزلى فى البنيات فائقة التوصيل Majed Abdelsalam Nashaat Moharram Abdelghani ; Supervised Tharwat Elsherbini , Yu . M. Shukrinov , Ali Yehia Ellithi - Cairo : Majed Abdelsalam Nashaat Moharram Abdel ghani , 2020 - 210 P . : charts ; 25cm
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 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
Nonequilibrium Spintronics Superconducting structures