Quantum interference oscillations of the superparamagnetic blocking in an Fe8 molecular nanomagnet

TL;DR

This paper demonstrates quantum interference effects in an Fe8 molecular nanomagnet, showing oscillations in magnetic susceptibility and blocking temperature as a function of magnetic field, linked to spin tunneling and multiplet mixing.

Contribution

It reveals the quantum interference oscillations in Fe8 nanomagnets and quantifies the mixing of excited multiplets in the ground state.

Findings

Oscillations in susceptibility and blocking temperature with magnetic field.

Quantum interference between spin tunneling paths.

Approximately 11.6% of excited multiplets in the ground state.

Abstract

We show that the dynamic magnetic susceptibility and the superparamagnetic blocking temperature of an Fe8 single molecule magnet oscillate as a function of the magnetic field Hx applied along its hard magnetic axis. These oscillations are associated with quantum interferences, tuned by Hx, between different spin tunneling paths linking two excited magnetic states. The oscillation period is determined by the quantum mixing between the ground S=10 and excited multiplets. These experiments enable us to quantify such mixing. We find that the weight of excited multiplets in the magnetic ground state of Fe8 amounts to approximately 11.6%.