Ballistic transport in ferromagnet–superconductor–ferromagnet trilayers with arbitrary orientation of magnetisations

Božović, Miloš; Radović, Z.

doi:10.1088/1367-2630/9/8/264

Cited by 9 publications

(11 citation statements)

References 59 publications

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“…Following the calculations of Refs. 32,33,34,35 , we express the normalized conductance of our system when a voltage eV is symmetrically applied to the junction with eV /2 in F L and (−eV /2) in F R as:…”

Section: Theorymentioning

confidence: 99%

“…Previous theoretical works have considered the MR in conventional (s-wave) F|S|F spin-valves for either exclusively P or AP configurations 33,34 , while recently Ref. 35 considered an arbitrary magnetization configuration. Here, we will investigate the influence of a d-wave superconducting order parameter on the MR, with particular emphasis on the role of zero-energy states.…”

Section: Theorymentioning

confidence: 99%

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Spin-transfer torque and magnetoresistance in superconducting spin valves

2009

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We study the spin-transfer torque and magnetoresistance of a ferromagnet|superconductor|ferromagnet spinvalve, allowing for an arbitrary magnetization misorientation and treating both s-wave and d-wave symmetries of the superconductor. We take fully into account Andreev reflection and also the spin-triplet correlations that are generated when the magnetizations are non-collinear. It is found that the torque and magnetoresistance are both strongly enhanced when topological zero-energy states are present at the interfaces, which is the case for dwave superconductors with a crystallographic orientation of [110] relative to the interface (dxy-wave symmetry). Moreover, we find that the magnetoresistance displays a strong oscillatory and non-monotonous behavior as a function of dS/ξ where dS and ξ are the interlayer width of the superconducting region and the superconducting coherence length, respectively. This feature is also attributed to the crossover from layers of size dS ∼ 2ξ to layers of size dS 2ξ, where the contribution to transport from zero-energy states gradually vanishes.

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Section: Theorymentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

Spin-transfer torque and magnetoresistance in superconducting spin valves

2009

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“…In most of the earlier works on tunnelling spectroscopy [97][98][99][100][101][102][103][104][105][106][107][108][109], it was found that the barrier thickness play a very significant role on the transport mechanism. However, the role of barrier thickness on spin transport is yet to be understood.…”

Section: A Spin Conductance Spectra At the F|ncsc Interfacementioning

confidence: 99%

“…Transport properties in several F|Singlet SC [97][98][99], F|Triplet SC [100][101][102][103][104][105] and F|NCSC [106][107][108][109] heterostructures had been studied earlier. However, the role of magnetization in spin transport, spin current [110][111][112][113][114][115] and its interplay with pair potential, magnetic field and RSOC of NCSC in F|NCSC|F SV is still need to be understood.…”

Section: Introductionmentioning

confidence: 99%

Spin transport and Spin Tunnelling Magneto-Resistance (STMR) of F|NCSC|F spin valve

Acharjee¹,

Goswami²

2020

Journal of Magnetism and Magnetic Materials

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In this work, we study the spin transport at the Ferromagnet|Noncentrosymmetric Superconductor (F|NCSC) junction of a Ferromagnet|Noncentrosymmetric Superconductor|Ferromagnet (F|NCSC|F) spin valve. We investigate the Tunnelling Spin-Conductance (TSC), spin current and Spin Tunnelling Magneto-Resistance (STMR), and their dependence on various important parameters like Rashba Spin-Orbit Coupling (RSOC), strength and orientation of magnetization, an external in-plane magnetic field, barrier strength and a significant Fermi Wavevector Mismatch (FWM) at the ferromagnetic and superconducting regions. The study has been carried out for different singlet-triplet mixing of the NCSC gap parameter. We develop Bogoliubov-de Gennes (BdG) Hamiltonian and use the extended Blonder -Tinkham -Klapwijk (BTK) approach along with the scattering matrix formalism to calculate the scattering coefficients. Our results strongly suggest that the TSC is highly dependent on RSOC, magnetization strength and its orientation, and singlet-triplet mixing of the gap parameter. It is observed that NCSC with moderate RSOC shows maximum conductance for a partially opaque barrier in presence of low external magnetic field. For a strongly opaque barrier and a nearly transparent barrier a moderate value and a low value of field respectively are found to be suitable. Moreover, NCSC with large singlet component is appeared to be useful. In addition, for NCSC with large RSOC and low magnetization strength, a giant STMR (%) is observed. We have also seen that the spin current is strongly magnetization orientation dependent. With the increase in bias voltage spin current increases in transverse direction, but the component along the direction of flow is almost independent. PACS numbers: 67.30.hj, 74.90.+n

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“…These structures have been studied using quasiclassical approach in both diffusive 1,2,3,9,10,11,12,13 and clean 14,15,16 limits by solving Usadel 17 and Eilenberger 18 equations, respectively, and by solving the Bogoliubov-de Gennes equation. 6,19,20,21,22 In the case of parallel (α = 0) magnetizations, SFS junctions, 23,24 besides spin-singlet superconducting correlations, only odd triplet correlations with zero total spin projection exist. These correlations penetrate into the ferromagnet over a short length scale determined by the exchange energy.…”

Section: Introductionmentioning

confidence: 99%

Odd triplet superconductivity in clean and moderately disordered SFFS junctions

Popović,

Radović

2009

Preprint

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We study the Josephson effect and pairing correlations in SFFS junctions that consist of conventional superconductors (S) connected through two metallic monodomain ferromagnets (F) with transparent and spin inactive interfaces. We solve the Eilenberger equations for arbitrary relative orientation of magnetizations of the two F layers in the clean limit and for moderate disorder in ferromagnets. Spatial variation of pair amplitudes, singlet fs, and odd in frequency triplet ft0 and ft1, with 0 and ±1 spin projections, as well as the Josephson current-phase relations are calculated for different values of the ferromagnetic layers thickness and angle α between in-plane magnetizations. In contrast to the dirty limit case, we find that for 0 < α < π both spin singlet and triplet pair amplitudes in F layers power-law decay in the same oscillatory manner with distance from the FS interfaces. This decay gets faster as the impurity-scattering rate in ferromagnets is increased. The computed triplet amplitude ft1 has opposite signs in the two magnet regions, penetrates into the superconductors and monotonically decays over the same distance, which is the superconducting coherence length, as the singlet amplitude fs saturates to the bulk value. We point out that influence of misorientation of magnetizations on the Josephson current can not be attributed directly to the appearance of odd triplet correlations.

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Ballistic transport in ferromagnet–superconductor–ferromagnet trilayers with arbitrary orientation of magnetisations

Cited by 9 publications

References 59 publications

Spin-transfer torque and magnetoresistance in superconducting spin valves

Spin-transfer torque and magnetoresistance in superconducting spin valves

Spin transport and Spin Tunnelling Magneto-Resistance (STMR) of F|NCSC|F spin valve

Odd triplet superconductivity in clean and moderately disordered SFFS junctions

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