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

Muon spin relaxation ( μ SR) 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 μ₀ H = 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. (paper)