Experimental evidence for a spin-Peierls-transition in $\alpha'-NaV_2O_5$

TL;DR

This study provides experimental evidence of a spin-Peierls transition in $ ext{NaV}_2 ext{O}_5$, showing a spin gap opening and lattice distortion at low temperatures, confirming its status as an inorganic spin-Peierls system.

Contribution

First magnetisation and Raman scattering measurements on $ ext{NaV}_2 ext{O}_5$ demonstrating a spin-Peierls transition with associated lattice distortion.

Findings

Susceptibility decreases below 34 K indicating a spin gap

Crystallographic distortion observed at transition

Transition temperature slightly depends on magnetic field

Abstract

We present the first measurements of magnetisation and Raman light scattering on $\alpha'-NaV_2O_5$ single crystals. Below 34 K, we observe a pronounced isotropic decrease of the susceptibility indicating the opening of a spin gap. The transition temperature is slightly field dependent. Raman experiments reveal a crystallographic distortion at the transition. Our results clearly establish $\alpha'-NaV_2O_5$ to be the second inorganic spin-Peierls system.