Chain Formation by Spin Pentamers in eta-Na9V14O35

TL;DR

This paper reveals that eta-Na9V14O35 forms a novel gapped ground state with spin pentamers creating linear chains, explaining its magnetic properties through combined experimental techniques.

Contribution

It demonstrates the formation of spin pentamers as multi-spin objects building linear chains, a new understanding of the ground state in eta-Na9V14O35.

Findings

Identification of spin pentamers as fundamental magnetic units

Evidence of a gapped ground state from multiple measurements

Exchange interactions comparable to high-temperature state

Abstract

The nature of the gapped ground state in the quasi-one-dimensional compound eta-Na9V14O35 cannot easily be understood, if one takes into account the odd number of spins on each structural element. Combining the results of specific heat, susceptibility and electron spin resonance measurements we show that eta-Na9V14O35 exhibits a novel ground state where multi-spin objects build up a linear chain. These objects - pentamers - consist of five antiferromagnetically arranged spins with effective spin 1/2. Their spatial extent results in an exchange constant along the chain direction comparable to the one in the high-temperature state.