Quantum Phase Interference and Neel-Vector Tunneling in Antiferromagnetic Molecular Wheels

TL;DR

This paper investigates the quantum magnetic behavior of an antiferromagnetic molecular wheel Fe18, demonstrating Neel-vector tunneling and quantum phase interference effects through various experimental measurements and semiclassical theory.

Contribution

It provides the first detailed experimental evidence of Neel-vector tunneling and quantum phase interference in a large antiferromagnetic molecular wheel, supported by comprehensive measurements and theoretical analysis.

Findings

Neel-vector tunneling accurately describes Fe18's low-temperature magnetism.

Magnetic torque oscillations reveal quantum phase interference effects.

Tunnel splitting oscillations are observed as a function of applied magnetic field.

Abstract

The antiferromagnetic molecular wheel Fe18 of eighteen exchange-coupled Fe(III) ions has been studied by measurements of the magnetic torque, the magnetization, and the inelastic neutron scattering spectra. The combined data show that the low-temperature magnetism of Fe18 is very accurately described by the Neel-vector tunneling (NVT) scenario, as unfolded by semiclassical theory. In addition, the magnetic torque as a function of applied field exhibits oscillations that reflect the oscillations in the NVT tunnel splitting with field due to quantum phase interference.