Observation of periodic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>π</mml:mi></mml:mrow></mml:math>-phase shifts in ferromagnet-superconductor multilayers

Shelukhin, Victor; Tsukernik, A.; Karpovski, M.; Blum, Yigal D.; Efetov, K. B.; Volkov, A. N.; Champel, Thierry; Eschrig, Matthias; Löfwander, Tomas; Schön, Gerd; Palevski, A.

doi:10.1103/physrevb.73.174506

Cited by 99 publications

(100 citation statements)

References 30 publications

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“…However, in many experiments this is not the case. In particular, in those performed with strong ferromagnets [9,12,14]. Theory considering an arbitrary value of hτ and l has been presented in Ref.…”

Section: Introductionmentioning

confidence: 99%

Scattering by magnetic and spin-orbit impurities and the Josephson current in superconductor-ferromagnet-superconductor junctions

2007

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We analyze the Josephson current in a junction consisting of two superconductors (S) and a ferromagnetic layer (F) for arbitrary impurity concentration. In addition to non-magnetic impurities, we consider also magnetic ones and spin-orbit scattering. In the limit of weak proximity effect we solve the linearized Eilenberger equation and derive an analytical expression for the Josephson critical current valid in a broad range of parameters. This expression enables us to obtain not only known results in the dirty and clean limits but also in a intermediate region of the impurity concentration, which may be very important for comparison with experimental data.

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Section: Introductionmentioning

confidence: 99%

Scattering by magnetic and spin-orbit impurities and the Josephson current in superconductor-ferromagnet-superconductor junctions

2007

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“…On the one hand, this interest is due to the progress in technology that allows a controllable fabrication of nanohybrid systems using a wide range of superconducting and magnetic materials. On the other hand, this interest is due to the discovery of new and interesting fundamental phenomena, as for example the so-called π state in S/F /S Josephson junctions [1][2][3][4][5][6][7][8][9] and more recently the long-range proximity effect mediated by odd-frequency triplet superconducting correlations in S/F structures [10][11][12][13][14][15][16][17] (for an overview, see Refs. [18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Electronic transport through ferromagnetic and superconducting junctions with spin-filter tunneling barriers

2012

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We present a theoretical study of the quasiparticle and subgap conductance of generic X/I sf /S M junctions with a spin-filter barrier I sf , where X is either a normal N or a ferromagnetic metal F and S M is a superconductor with a built-in exchange field. Our study is based on the tunneling Hamiltonian and the Green's-function technique. First, we focus on the quasiparticle transport, both above and below the superconducting critical temperature. We obtain a general expression for the tunneling conductance which is valid for arbitrary values of the exchange field and arbitrary magnetization directions in the electrodes and in the spin-filter barrier. In the second part, we consider the subgap conductance of a N/I sf /S junction, where S is a conventional superconductor. In order to account for the spin-filter effect at interfaces, we heuristically derive boundary conditions for the quasiclassical Green's functions. With the help of these boundary conditions, we show that the proximity effect and the subgap conductance are suppressed by spin filtering in a N/I sf /S junction. Our work provides useful tools for the study of spin-polarized transport in hybrid structures both in the normal and in the superconducting state.

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“…The key to this process is magnetic inhomogeneity at the S-F interface. For example, consider a S-F -F-F -S Josephson junction [7]: If the F and F layer magnetizations are collinearly aligned, spin-zero triplet pairs form which, like singlet pairs, are short ranged [8] with a coherence length in F metals of only a few nanometers (Ni [9][10][11][12], NiFe [13,14], Co [11,15,16], and Fe [17,18]). However, if F and F layer magnetizations are noncollinearly aligned spin-one triplet pairs form and the coherence length is greatly extended [19][20][21][22][23][24][25][26][27].…”

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Giant triplet proximity effect in superconducting pseudo spin valves with engineered anisotropy

et al. 2014

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The proximity coupling of a thin superconducting layer and an inhomogeneous ferromagnet can lead to a significant reduction of the critical temperature due to the generation of spin-polarized triplet Cooper pairs. We report critical temperature measurements of Co/Cu/NiFe(Py)/Cu/Nb superconducting pseudo spin valves (PSVs) in which the magnetization of the soft layer (Py) can be independently rotated in-plane with a magnetic field to create an angle (θ ) between it and the magnetization of Co. Here we observe results consistent with spin-triplet theory and demonstrate large changes in T C up to −120 mK as the Py layer is rotated from 0°(Co and Py are parallel) to 90°(Co and Py are orthogonal), which offers the potential for active control of the superconducting state. The key to this achievement is engineered magnetic anisotropy in Py, which enables well-defined control over the magnetization configuration of the PSV.

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Observation of periodicπ-phase shifts in ferromagnet-superconductor multilayers

Cited by 99 publications

References 30 publications

Scattering by magnetic and spin-orbit impurities and the Josephson current in superconductor-ferromagnet-superconductor junctions

Scattering by magnetic and spin-orbit impurities and the Josephson current in superconductor-ferromagnet-superconductor junctions

Electronic transport through ferromagnetic and superconducting junctions with spin-filter tunneling barriers

Giant triplet proximity effect in superconducting pseudo spin valves with engineered anisotropy

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