Spin-memory loss at Co/Ru interfaces

TL;DR

This study measures the spin-memory-loss parameter at Co/Ru interfaces using Josephson junctions and CPP-GMR, finding consistent values from different methods but noting an unexplained discrepancy for spin-singlet transmission.

Contribution

The paper provides the first direct measurements of the spin-memory-loss parameter at Co/Ru interfaces using multiple techniques, highlighting method consistency and discrepancies.

Findings

Measured $oldsymbol{ ext{delta}}_{Co/Ru}$ as 0.34 from CPP-GMR

Obtained $oldsymbol{ ext{delta}}_{Co/Ru}$ as 0.35 from spin-triplet transmission

Discrepancy in $oldsymbol{ ext{delta}}_{Co/Ru}$ for spin-singlet transmission remains unexplained

Abstract

We have determined the spin-memory-loss parameter, $\delta_{Co/Ru}$, by measuring the transmission of spin-triplet and spin-singlet Cooper pairs across Co/Ru interfaces in Josephson junctions and by Current-Perpendicular-to-Plane Giant Magnetoresistance (CPP-GMR) techniques. The probability of spin-memory loss at the Co/Ru interface is $(1-exp(-\delta_{Co/Ru}))$. From the CPP-MR, we obtain $\delta_{Co/Ru} = 0.34^{+0.04}_{-0.02}$ that is in good agreement with $\delta_{Co/Ru} = 0.35 \pm 0.08$ obtained from spin-triplet transmission. For spin-singlet transmission, we have $\delta_{Co/Ru} = 0.64 \pm 0.05$ that is different from that obtained from CPP-GMR and spin-triplet transmission. The source of this difference is not understood.