Onset of magnetic correlations in LiY 1-x Ho x F 4 with 0.002 <= x <= 0.05 studied via μSR

摘要: We are using μSR to probe the evolution of magnetism from single-ion spin glass behaviour in LiY1-xHoxF4 with increasing x. For x = 0.002 Ho dynamics exhibit similar that observed molecular magnets. Near T≈ 10 K, energy gap between ground state electronic doublet and first excited singlet levels, we find longitudinal depolarization rate exhibits a peak depends on Larmor frequency. At temperatures T << K sharp reductions transverse field rates vicinity magnetic induced (avoided) level crossings (ALCs) hyperfine-split manifold. This is attributed reduction quasistatic disorder due resonant fluctuations at frequencies much larger than muon As concentration increased toward 0.05, correlations become significant, changing into plateau, significantly broadening changes ALCs.