First-principles study of the spin-mixing conductance in Pt/Ni$_{81}$Fe$_{19}$ junctions

TL;DR

This study uses first-principles calculations to analyze how interface quality affects spin-mixing conductance in Pt/NiFe junctions, providing insights for optimizing spintronic device performance.

Contribution

It offers a theoretical evaluation of spin-mixing conductance in Pt/NiFe junctions, highlighting the impact of interface roughness and proposing methods to enhance conductance.

Findings

Interface roughness increases SMC compared to ideal interfaces.

Calculated SMC aligns well with recent experimental data.

Adding a magnetic metal layer can further boost SMC.

Abstract

Based on the spin-pumping theory and first-principles calculations, the spin-mixing conductance (SMC) is theoretically studied for Pt/Permalloy (Ni$_{81}$Fe$_{19}$, Py) junctions. We evaluate the SMC for ideally clean Pt/Py junctions and examine the effects of interface randomness. We find that the SMC is generally enhanced in the presence of interface roughness as compared to the ideally clean junctions. Our estimated SMC is in good quantitative agreement with the recent experiment for Pt/Py junctions. We propose possible routes to increase the SMC in Pt/Py junctions by depositing a foreign magnetic metal layer in Pt, offering guidelines for designing the future spintronic devices.