Ultrafast Spin Dynamics in Nickel

TL;DR

This paper investigates ultrafast spin dynamics in nickel using exact diagonalization, revealing how exchange interaction and spin-orbit coupling influence femtosecond relaxation, with implications for accelerating spin processes in experiments.

Contribution

It provides a detailed theoretical analysis of femtosecond spin relaxation in Ni, highlighting the roles of exchange interaction and spin-orbit coupling on ultrafast timescales.

Findings

Intrinsic spin dynamics occurs within about 10 fs.

Laser pulse characteristics can slow down observed dynamics.

Room remains to accelerate spin dynamics experimentally.

Abstract

The spin dynamics in Ni is studied by an exact diagonalization method on the ultrafast time scale. It is shown that the femtosecond relaxation of the magneto-optical response results from exchange interaction and spin-orbit coupling. Each of the two mechanisms affects the relaxation process differently. We find that the intrinsic spin dynamics occurs during about 10 fs while extrinsic effects such as laser-pulse duration and spectral width can slow down the observed dynamics considerably. Thus, our theory indicates that there is still room to accelerate the spin dynamics in experiments.