Anomalous current in diffusive ferromagnetic Josephson junctions

Силаев, М. А.; Tokatly, I. V.; Bergeret, F. S.

doi:10.1103/physrevb.95.184508

Cited by 85 publications

(96 citation statements)

References 64 publications

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“…The spontaneous phase shift of Josephson current has been obtained in several FM/SC systems [25,27,30,35,[41][42][43][44][45][46][47][48][49][50][51][52][53][54]]. Here we demonstrate that this effect is essential only for the case of strong ferromagnets.…”

Section: Spontaneous Josephson Current Through Strong Ferromagnetssupporting

confidence: 54%

Gauge theory of the long-range proximity effect and spontaneous currents in superconducting heterostructures with strong ferromagnets

2017

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Gauge theory of the long-range proximity effect and spontaneous currents in superconducting heterostructures with strong ferromagnets Bobkova, I. V.; Silaev, Mikhail Bobkova, I. V., Bobkov, A. M., & Silaev, M. (2017). Gauge theory of the long-range proximity effect and spontaneous currents in superconducting heterostructures with strong ferromagnets. Physical Review B, 96 (9) We present the generalized quasiclassical theory of the long-range superconducting proximity effect in heterostructures with strong ferromagnets, where the exchange splitting is of the order of Fermi energy. In the ferromagnet the propagation of equal-spin Cooper pairs residing on the spin-split Fermi surfaces is shown to be governed by the spin-dependent Abelian gauge field which results either from the spin-orbital coupling or from the magnetic texture. This additional gauge field enters into the quasiclassical equations in superposition with the usual electromagnetic vector potential and results in the generation of spontaneous superconducting currents and phase shifts in various geometries which provide the sources of long-range spin-triplet correlations. We derive the Usadel equations and boundary conditions for the strong ferromagnet and consider several generic examples of the Josephson systems supporting spontaneous currents.

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Section: Spontaneous Josephson Current Through Strong Ferromagnetssupporting

confidence: 54%

Gauge theory of the long-range proximity effect and spontaneous currents in superconducting heterostructures with strong ferromagnets

2017

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“…(6) it is apparent that the current density is nonzero at zero phase difference ϕ = 0 when hr = 0. It is worth mentioning that the appearance of a ϕ0 phase shift in the supercurrent has theoretically been discussed in various situations 13,16,26,27,[62][63][64][65][66][67][68][69][70][71][72] and observed in experiments 73,74 . In structures where the spin orbit meditated coupling is available, its interplay with a properly oriented Zeeman(-like) field results in a supercurrent flow perpendicular to the junction interfaces at zero phase difference 13,16,26,27,71,72 .…”

Section: Methods and Resultsmentioning

confidence: 99%

Spontaneous supercurrent and φ0 phase shift parallel to magnetized topological insulator interfaces

Alidoust

Hamzehpour

2017

Phys. Rev. B

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Employing a Keldysh-Eilenberger technique, we theoretically study the generation of a spontaneous supercurrent and the appearance of the ϕ0 phase shift parallel to uniformly in-plane magnetized superconducting interfaces made of the surface states of a three-dimensional topological insulator. We consider two weakly coupled uniformly magnetized superconducting surfaces where a macroscopic phase difference between the s-wave superconductors can be controlled externally. We find that, depending on the magnetization strength and orientation on each side, a spontaneous supercurrent due to the ϕ0-states flows parallel to the interface at the junction location. Our calculations demonstrate that nonsinusoidal phase relations of current components with opposite directions result in maximal spontaneous supercurrent at phase differences close to π. We also study the Andreev subgap channels at the interface and show that the spin-momentum locking phenomenon in the surface states can be uncovered through density of states studies. We finally discuss realistic experimental implications of our findings.

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“…However, the applicability of these methods assumes that the exchange field h in the ferromagnet should be much smaller than the Fermi energy h ≪ E F and the use of the Usadel equations implies even more restrictive conditions hτ ≪ 1, where τ is the electrons scattering time. These circumstances lead to the fact that some subtle qualitative effects may be missed by the quasiclassical approach, see, for example [8][9][10] . Moreover, a lot of experimental activities with the S/F heterostructures deal with the strong ferromagnets (or even halfmetals [11][12][13] ) for which the quasiclassical approximation cannot provide an adequate quantitative description.…”

Section: Introductionmentioning

confidence: 99%

Josephson current through a ferromagnetic bilayer: Beyond the quasiclassical approximation

et al. 2019

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Based on the Bogoliubov-de Gennes equations, we provide an exact numerical solution for the critical current of Josephson junctions with a composite ferromagnetic bilayer. We demonstrate that for the antiparallel orientation of the magnetic moments of the bilayer, the presence of a potential barrier at the bilayer interface results in large oscillations of the critical current as a function of ferromagnet thickness and/or exchange field. Because of this, and remarkably, in the range of small exchange field and thicknesses, the magnetism leads to the increase of the critical current. This effect is well pronounced at low temperature but disappears near Tc. If the potential barrier is replaced by a spin-active barrier at the bilayer interface the conventional 0-π transition, similar to the case of an uniform ferromagnetic Josephson junction, is observed. Strikingly, for a parallel orientation of the magnetic moments of the bilayer, the presence of the spin-active barrier restores the anomalous behavior-potential barrier in the antiparallel case. These behaviors result from the resonant tunneling of Cooper pairs across the composite barrier-an effect related to the spindependent Fermi vector in the presence of the ferromagnets' exchange field.

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Anomalous current in diffusive ferromagnetic Josephson junctions

Cited by 85 publications

References 64 publications

Gauge theory of the long-range proximity effect and spontaneous currents in superconducting heterostructures with strong ferromagnets

Gauge theory of the long-range proximity effect and spontaneous currents in superconducting heterostructures with strong ferromagnets

Spontaneous supercurrent and φ0 phase shift parallel to magnetized topological insulator interfaces

Josephson current through a ferromagnetic bilayer: Beyond the quasiclassical approximation

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