Magnetization dynamics in the single-molecule magnet Fe8 under pulsed microwave irradiation

TL;DR

This study investigates the magnetization dynamics of the Fe8 single-molecule magnet under pulsed microwave radiation, revealing the significant effects of phonon bottleneck and spin diffusion on relaxation behavior.

Contribution

It provides new insights into the relaxation mechanisms in Fe8, highlighting the roles of phonon bottleneck and spin diffusion through experimental analysis.

Findings

Phonon bottleneck causes relaxation times of 10-100 ms.

Spin diffusion influences magnetization relaxation.

Sample size and irradiation method affect relaxation dynamics.

Abstract

We present measurements on the single molecule magnet Fe8 in the presence of pulsed microwave radiation at 118 GHz. The spin dynamics is studied via time resolved magnetization experiments using a Hall probe magnetometer. We investigate the relaxation behavior of magnetization after the microwave pulse. The analysis of the experimental data is performed in terms of different contributions to the magnetization after-pulse relaxation. We find that the phonon bottleneck with a characteristic relaxation time of 10 to 100 ms strongly affects the magnetization dynamics. In addition, the spatial effect of spin diffusion is evidenced by using samples of different sizes and different ways of the sample's irradiation with microwaves.