Hybrid superconducting mesa-heterostructure with manganite-ruthenate interlayer

K Y Constantinian,A E Sheyerman,Y V Kislinskii,G A Ovsyannikov,A Kalabukhov,D Winkler,A V Shadrin

doi:10.1088/1742-6596/507/4/042007

Abstract

We present experimental data on Josephson effect in hybrid superconducting mesa-heterostructures (HSMH) with composite manganite-ruthenate interlayer. The HSMH base electrode consisted of the cuprate superconductor YBa2Cu3O7 grown epitaxially on a NdGaO substrate using laser ablation. The interlayer was composed from in-situ deposited SrRuO3 (F1) and La0.7Sr0.3MnO3 (F2) thin films, each characterized by different directions of magnetization. The top electrode was Nb/Au thin film. A superconducting current was observed when the interlayer thickness was well above the correlation length, determined by the exchange field in F1 and F2. Obtained IC(H) dependences and non-sinusoidal current-phase relation evaluated from microwave measurements are discussed in terms of generation of long-range spin triplet superconducting current component in heterostructures with interfaces of singlet superconductors and bilayer ferromagnetic materials with different spatial directions of magnetization.

Highlights

In superconducting heterostructures with a non-uniform magnetized ferromagnetic layer (F) between two singlet superconductors (S) a long-range triplet superconducting correlations may occur [1]
The superconducting current was observed in all hybrid superconducting mesa-heterostructures (HSMH) with a total thickness d of the composite Minterlayer up to 53 nm, which is much larger than the coherence lengths in F1 and F2, determined by the exchange field
Control measurements of the HSMH with only the LSMO [16] or the SRO interlayer, showed [22] that the critical current is absent if the SRO and LSMO films are thicker than d1=14 nm and d2=2 nm, respectively

Summary

Introduction

In superconducting heterostructures with a non-uniform magnetized ferromagnetic layer (F) between two singlet superconductors (S) a long-range triplet superconducting correlations may occur [1]. 3. Results and discussion The superconducting current was observed in all HSMH with a total thickness d of the composite Minterlayer up to 53 nm, which is much larger than the coherence lengths in F1 and F2, determined by the exchange field.

Results

Conclusion