Evidence for spin liquid ground state in SrDy2O4 frustrated magnet probed by μSR

N Gauthier,C Baines,A D Bianchi,M Kenzelmann,B Prévost,V Pomjakushin,R J Cava,A Amato

doi:10.1088/1742-6596/828/1/012014

Abstract

Muon spin relaxation (μSR) measurements were carried out on SrDy2O4, a frustrated magnet featuring short range magnetic correlations at low temperatures. Zero-field muon spin depolarization measurements demonstrate that fast magnetic fluctuations are present from T = 300 K down to 20 mK. The coexistence of short range magnetic correlations and fluctuations at T = 20 mK indicates that SrDy2O4 features a spin liquid ground state. Large longitudinal fields affect weakly the muon spin depolarization, also suggesting the presence of fast fluctuations. For a longitudinal field of μ0H = 2 T, a non-relaxing asymmetry contribution appears below T = 6 K, indicating considerable slowing down of the magnetic fluctuations as field-induced magnetically-ordered phases are approached.

Highlights

In magnetically frustrated systems, competing interactions can inhibit long range order at low temperatures and enforce highly degenerate ground states
A stretched exponential is the most appropriate function to describe the data over the full temperature range and the experimental spectra were fitted by: A(t) = ase−(λt)β + ab where λ is the relaxation rate, β is an exponent stretching the exponential function, as is the sample initial asymmetry and ab is a constant asymmetry arising from muons missing the sample, with as + ab = a0
In SrDy2O4, the muon spin depolarization is weakly affected by a longitudinal field of μ0H = 1 T while a non-relaxing asymmetry contribution attributed to static moments emerges at μ0H = 2 T (Fig. 2b)

Summary

Introduction

In magnetically frustrated systems, competing interactions can inhibit long range order at low temperatures and enforce highly degenerate ground states. This can give rise to novel states of matter such as spin liquids, in which strongly fluctuating magnetic degrees of freedom persist to the lowest temperatures [1]. The SrLn2O4 (Ln = Gd, Tb, Dy, Ho, Er, Tm and Yb) compounds form a family of frustrated rare-earth magnets [9, 10] They crystallize in an orthorhombic structure (space group Pnam) with two inequivalent rare-earth ion sites, each forming one-dimensional zig-zag chains along the c-axis.

Experimental details

Experimental results

Discussion and summary