Spin frustration effects in an odd-member antiferromagnetic ring and the magnetic Moebius strip

TL;DR

This paper investigates the magnetic properties and spin frustration effects in an odd-member antiferromagnetic ring with chromium and nickel ions, visualized as a Moebius strip, revealing delocalized frustration and rigid antiparallel alignment at the nickel site.

Contribution

It introduces a novel visualization of spin frustration in a bimetallic ring as a Moebius strip and provides detailed EPR analysis of the frustration distribution.

Findings

Frustration is delocalized on the chromium chain.

Antiparallel alignment is more rigid at the nickel site.

First excited states are close in energy to the ground state.

Abstract

The magnetic properties of the first odd-member antiferromagnetic ring comprising eight chromium(III) ions, S=3/2 spins, and one nickel(II) ion, S=1 spin, are investigated. The ring possesses an even number of unpaired electrons and a S=0 ground state but, due to competing AF interactions, the first excited spin states are close in energy. The spin frustrated ring is visualized by a Moebius strip. The ?knot? of the strip represents the region of the ring where the AF interactions are more frustrated. In the particular case of this bimetallic ring electron paramagnetic resonance (EPR) has unambiguously shown that the frustration is delocalized on the chromium chain, while the antiparallel alignment is more rigid at the nickel site.