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Spin-Triplet Superconducting Current in Metal-Oxide Heterostructures With Composite Ferromagnetic Interlayer

K. Constantinian ; G. Ovsyannikov ; A. Sheyerman ; Y. Kislinskii ; A. Shadrin ; Alexei Kalaboukhov (Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik) ; L. Mustafa ; Y. Khaydukov ; Dag Winkler (Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik)
Ieee Transactions on Applied Superconductivity (1051-8223). Vol. 26 (2016), 3,
[Artikel, refereegranskad vetenskaplig]

Superconducting heterostructures fabricated from oxide superconductor YBa2Cu2O7-delta and a composite ferromagnet La0.7Sr0.3MnO3/SrRuO3 interlayer and Au/Nb counter electrode were studied experimentally. Superconducting current was observed at magnetic field H raised up to 2000 Oe, which is greater than saturation magnetic field of manganite La0.7Sr0.3MnO3 (of order 100 Oe) and greater by a few orders than the value of magnetic field corresponding to penetration of one magnetic flux quantum. Microwave measurements of integer and half-integer Shapiro steps in conditions when relatively low external magnetic fieldH < 30 Oe was applied showed that the second harmonic in the current-phase relation of superconducting current becomes as big as the first harmonic. Fourier analysis of I-C(H) dependence allows extracting the components of fractional periods in I-C(H) function that also confirms a deviation from the sinusoidal current-phase relation. The obtained experimental data are explained by theoretical models that predict a huge enhancement of the second harmonic of the spin-triplet component in the superconducting current. The current-phase relation could be controlled by an external magnetic field, changing the directions of magnetization in the composite bilayer ferromagnet, which is inserted between two spin-singlet superconductors.

Nyckelord: Composite ferromagnet, current-phase relations, long-range proximity effect, spin-triplet pairing, superconducting heterostructure



Denna post skapades 2016-04-22. Senast ändrad 2016-10-27.
CPL Pubid: 235060

 

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Institutioner (Chalmers)

Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik

Ämnesområden

Elektroteknik och elektronik

Chalmers infrastruktur