Odd spin-triplet superconductivity in a multilayered superconductor-ferromagnet Josephson junction

Volkov, A. N.; Efetov, K. B.

doi:10.1103/physrevb.81.144522

Cited by 75 publications

(92 citation statements)

References 82 publications

(152 reference statements)

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“…[22] for structures with long-range triplet superconducting correlations. Further increase in d F/F resulted in a decrease of j C as expected from theoretical calculations [21][22][23].…”

Section: Josephson Current In Mesa Structuressupporting

confidence: 73%

“…The SF reflectivities R +− and R −+ depend only on the magnetic potential ρ SF (z) = B ⊥ (z). PNR thus allows the determination of depth profiles of the vector magnetization, and the experimental definition of the level of magnetic noncollinearity, which is an important parameter in the theory of triplet superconductivity [18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

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Evidence for spin-triplet superconducting correlations in metal-oxide heterostructures with noncollinear magnetization

et al. 2014

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Heterostructures composed of ferromagnetic La 0.7 Sr 0.3 MnO 3 , ferromagnetic SrRuO 3 , and superconducting YBa 2 Cu 3 O 6+x were studied experimentally. Structures of composition Au/La 0.7 Sr 0.3 MnO 3 /SrRuO 3 / YBa 2 Cu 3 O 6+x were prepared by pulsed laser deposition, and their high quality was confirmed by x-ray diffraction and reflectometry. A noncollinear magnetic state of the heterostructures was revealed by means of superconducting quantum interference device magnetometry and polarized neutron reflectometry. We have further observed superconducting currents in mesa structures fabricated by deposition of a second superconducting Nb layer on top of the heterostructure, followed by patterning with photolithography and ion-beam etching. Josephson effects observed in these mesa structures can be explained by the penetration of a triplet component of the superconducting order parameter into the magnetic layers.

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“…[22] for structures with long-range triplet superconducting correlations. Further increase in d F/F resulted in a decrease of j C as expected from theoretical calculations [21][22][23].…”

Section: Josephson Current In Mesa Structuressupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Evidence for spin-triplet superconducting correlations in metal-oxide heterostructures with noncollinear magnetization

et al. 2014

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“…According to theory, if the two angles θ 1 and θ 2 have the same sign, then the junction will have π coupling; if they have opposite signs, the junction will have 0 coupling. [20][21][22] (We define the angles by the constraint |θ 1 |, |θ 2 | < π.) Since the magnetic layers in our samples consist of many domains when the samples are first grown, we would expect the Josephson coupling in our junctions to exhibit a random spatially-varying pattern of 0-coupling and π-coupling across the junction area.…”

Section: Introductionmentioning

confidence: 99%

Area-dependence of spin-triplet supercurrent in ferromagnetic Josephson junctions

2012

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Josephson junctions containing multiple ferromagnetic layers can carry spin-triplet supercurrent under certain conditions. Large-area junctions containing multiple domains are expected to have a random distribution of 0 or π coupling across the junction surface, whereas magnetized samples should have uniquely π coupling everywhere. We have measured the area dependence of the critical current in such junctions, and confirm that the critical current scales linearly with area in magnetized junctions. For as-grown (multi-domain) samples, the results are mixed. Samples grown on a thick Nb base exhibit critical currents that scale sub-linearly with area, while samples grown on a smoother Nb/Al multilayer base exhibit critical currents that scale linearly with area. The latter results are consistent with a theoretical picture due to Zyuzin and Spivak that predicts that the as-grown samples should have global π/2 coupling.

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“…Note that the critical current maximum of the TSC in superconducting structures with a two-layer composite ferromagnetic interlayer is predicted at thicknesses that are about equal to the coherence length. 66 Since the mean free path l in oxide materials (SRO and LSMO) is sufficiently small, 67,68 we can assume that the electron transport is diffusive in nature. By using the measured dependences R(T) for SRO and LSMO films, we get n LSMO F % 8 nm and n SRO F % 3 nm, respectively.…”

Section: The Critical Current Of a Mesastructurementioning

confidence: 99%

Magnetic proximity effect and superconducting triplet correlations at the cuprate superconductor and oxide spin valve interface

Ovsyannikov

Constantinian

Демидов

et al. 2016

Low Temperature Physics

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A heterostructure consisting of a cuprate superconductor YBa 2 Cu 3 O 7-d and a ruthenate/manganite (SrRuO 3 /La 0.7 Sr 0.3 MnO 3 ) spin valve was studied using SQUID magnetometry, ferromagnetic resonance, and neutron reflectometry. It is shown that because of the magnetic proximity effect a magnetic moment is excited in the superconducting portion of the heterostructure, whereas the magnetic moment in the spin valve becomes suppressed. The experimentally obtained value of a typical penetration depth of a magnetic moment into the superconductor is significantly greater than the coherence length of the cuprate superconductor, which indicates that the induced magnetic moment mechanism of Cu atoms is dominant. The mesastructure prepared by adding niobium film as a second superconducting electrode to the existing heterostructure, exhibited a superconducting current (dc Josephson effect) at interlayer thicknesses that are much greater than the coherence length of the ferromagnetic materials. The maximum of the critical current density dependence on the thickness of the spin valve material corresponds to the interlayer coherence length, which agrees with the theoretical predictions associated with spin-triplet pairing. The superconducting current is observed at magnetic fields that are two orders of magnitude greater than the field corresponding to the occurrence of one magnetic flux quantum in the mesastructure. The ratio of the second harmonic of the current-phase dependence of the mesastructure superconducting current to the first, determined according to the dependence of the Shapiro steps on the amplitude of microwave exposure, did not exceed 50%. Published by AIP Publishing. [http://dx

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Odd spin-triplet superconductivity in a multilayered superconductor-ferromagnet Josephson junction

Cited by 75 publications

References 82 publications

Evidence for spin-triplet superconducting correlations in metal-oxide heterostructures with noncollinear magnetization

Evidence for spin-triplet superconducting correlations in metal-oxide heterostructures with noncollinear magnetization

Area-dependence of spin-triplet supercurrent in ferromagnetic Josephson junctions

Magnetic proximity effect and superconducting triplet correlations at the cuprate superconductor and oxide spin valve interface

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