Spin-Triplet Superconducting Current in Metal-Oxide Heterostructures With Composite Ferromagnetic Interlayer
Artikel i vetenskaplig tidskrift, 2016

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.

current-phase relations

long-range proximity effect

spin-triplet pairing

superconducting heterostructure

Composite ferromagnet

Författare

K. Y. Constantinian

National Research University of Electronic Technology (MIET)

Gennady Ovsyannikov

National Research University of Electronic Technology (MIET)

A. E. Sheyerman

National Research University of Electronic Technology (MIET)

Yu V. Kislinskiǐ

National Research University of Electronic Technology (MIET)

A. V. Shadrin

National Research University of Electronic Technology (MIET)

Alexei Kalaboukhov

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

L. Mustafa

Max Planck-institutet

Y. N. Khaydukov

Max Planck-institutet

Dag Winkler

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

IEEE Transactions on Applied Superconductivity

1051-8223 (ISSN)

Vol. 26

Ämneskategorier

Elektroteknik och elektronik

DOI

10.1109/tasc.2016.2522300