Spin wave excitations: The main source of the temperature dependence of Interlayer exchange coupling in nanostructures

TL;DR

This study combines quantum mechanical calculations and ferromagnetic resonance experiments to identify that magnon excitations account for approximately 75% of the temperature-induced reduction in interlayer exchange coupling in nanostructures.

Contribution

It provides a quantitative separation of the contributions of magnon excitations and interface effects to the temperature dependence of interlayer exchange coupling.

Findings

Magnon excitations cause about 75% of the coupling reduction from zero to room temperature.

Remaining 25% of the reduction is due to temperature effects at interfaces and in the quantum well.

Quantum calculations and FMR experiments agree on the dominant role of magnons.

Abstract

Quantum mechanical calculations based on an extended Heisenberg model are compared with ferromagnetic resonance (FMR) experiments on prototype trilayer systems Ni_7/Cu_n/Co_2/Cu(001) in order to determine and separate for the first time quantitatively the sources of the temperature dependence of interlayer exchange coupling. Magnon excitations are responsible for about 75% of the reduction of the coupling strength from zero to room temperature. The remaining 25% are due to temperature effects in the effective quantum well and the spacer/magnet interfaces.