Phase shift effects of the I-V characteristics of zero-field current spikes in long Josephson junctions

1987 ◽  
Vol 23 (2) ◽  
pp. 1102-1105 ◽  
Author(s):  
A. Ferrigno ◽  
U. Gamberdella ◽  
S. Pace

During last decade, considerable efforts were made to achieve coherent emission from stacks of many Josephson junctions. It is known that strong emission from a junction in the presence of external magnetic field appears at the so-called Fiske steps in the IV-characteristic at voltages which correspond to frequencies of geometrical resonances. However, it is possible to obtain resonant steps in long junctions without external magnetic field. The periodical movement of fluxons is excited due to some disorder in the distribution of critical currents along junctions. The so-called zero-field steps are formed in the IV-curve due to the interaction of fluxons with oscillations of voltage at Josephson frequencies. We investigated numerically IV-characteristics and the dependence of the average square of ac voltage at the end of the stack of two long Josephson junctions on the average voltage. Junctions interacted inductively with each other. We introduced not only the Gaussian distribution of critical currents along junctions but also the Gaussian distribution of coefficients of the interaction between junctions (mutual inductances). Zero-field steps in the IV-characteristic were found at voltages which corresponded to frequencies of in-phase collective modes in the stack as well as to frequencies of uncoupled junctions. Zero-field steps appeared in the hysteretic region of the IV-curve. There appeared also jumps of voltage from the resistive branch to the zero-field step. We showed that there existed distributions of mutual inductances along junctions which provided jumps to voltages at which the average square of ac voltage at the end of the stack (which is proportional to power of emission) was larger than that for the stack with the uniform distribution of mutual inductances.


2002 ◽  
Vol 92 (7) ◽  
pp. 3853-3862 ◽  
Author(s):  
A. Benabdallah ◽  
J. G. Caputo

2018 ◽  
Vol 4 (5) ◽  
Author(s):  
Jean-Noël Fuchs ◽  
Frédéric Piéchon ◽  
Gilles Montambaux

A generalized semiclassical quantization condition for cyclotron orbits was recently proposed by Gao and Niu , that goes beyond the Onsager relation . In addition to the integrated density of states, it formally involves magnetic response functions of all orders in the magnetic field. In particular, up to second order, it requires the knowledge of the spontaneous magnetization and the magnetic susceptibility, as was early anticipated by Roth . We study three applications of this relation focusing on two-dimensional electrons. First, we obtain magnetic response functions from Landau levels. Second we obtain Landau levels from response functions. Third we study magnetic oscillations in metals and propose a proper way to analyze Landau plots (i.e. the oscillation index nn as a function of the inverse magnetic field 1/B1/B) in order to extract quantities such as a zero-field phase-shift. Whereas the frequency of 1/B1/B-oscillations depends on the zero-field energy spectrum, the zero-field phase-shift depends on the geometry of the cell-periodic Bloch states via two contributions: the Berry phase and the average orbital magnetic moment on the Fermi surface. We also quantify deviations from linearity in Landau plots (i.e. aperiodic magnetic oscillations), as recently measured in surface states of three-dimensional topological insulators and emphasized by Wright and McKenzie .


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Alexandre Assouline ◽  
Cheryl Feuillet-Palma ◽  
Nicolas Bergeal ◽  
Tianzhen Zhang ◽  
Alireza Mottaghizadeh ◽  
...  

1999 ◽  
Vol 9 (2) ◽  
pp. 4558-4561 ◽  
Author(s):  
G. Carapella ◽  
G. Costabile ◽  
J. Mygind ◽  
N.F. Pedersen

1980 ◽  
Vol 41 (5-6) ◽  
pp. 583-593 ◽  
Author(s):  
Yih-Shun Gou ◽  
Chien-Shine Chung ◽  
Timothy Chi Chow

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