Breaking the ring: $^{53}$Cr-NMR on the Cr$_{8}$Cd molecular nanomagnet

TL;DR

This study uses $^{53}$Cr-NMR spectroscopy to analyze the local spin densities and spin arrangements in the Cr$_{8}$Cd molecular nanomagnet, providing insights into finite antiferromagnetic spin chains and their magnetic behavior.

Contribution

It presents the first detailed $^{53}$Cr-NMR characterization of Cr$_{8}$Cd, confirming theoretical predictions of non-collinear spin arrangements in finite AF open chains.

Findings

NMR resonant frequencies match theoretical local spin densities

Confirmed non-collinear spin arrangement in Cr$_{8}$Cd

Validated the model of Cr$_{8}$Cd as a finite AF open chain

Abstract

An accurate experimental characterization of finite antiferromagnetic (AF) spin chains is crucial for controlling and manipulating their magnetic properties and quantum states for potential applications in spintronics or quantum computation. In particular, finite AF chains are expected to show a different magnetic behaviour depending on their length and topology. Molecular AF rings are able to combine the quantum-magnetic behaviour of AF chains with a very remarkable tunability of their topological and geometrical properties. In this work we measure the $^{53}$Cr-NMR spectra of the Cr$_{8}$Cd ring to study the local spin densities on the Cr sites. Cr$_{8}$Cd can in fact be considered a model system of a finite AF open chain with an even number of spins. The NMR resonant frequencies are in good agreement with the theoretical local spin densities, by assuming a core polarization feld AC = -12.7 T/$\mu_B$. Moreover, these NMR results confirm the theoretically predicted non-collinear spin arrangement along the Cr$_{8}$Cd ring, which is typical of an even-open AF spin chain.