Cu-NMR study on the disordered quantum spin magnet with the Bose-glass ground state

Abstract

Cu-NMR study has been performed on the disordered spin-gap system Tl1−xKxCuCl3 In the high-field H > HC=∆/µB, where ∆ is the spin-gap, the hyperfine field becomes extremely inhomogeneous at low temperatures due to the field-induced magnetic order, indicating that the ordered spin state must be different from the pure TlCuCl3. In the low field H < HC, a saturating behavior in the longitudinal nuclear spin relaxation rate T −1 1 was observed at low temperatures, indicating existence of the magnetic ground state proposed to be Bose-glass phase by Fisher.

Quantum critical behavior in the highly random systemTl1−xKxCuCl3probed by zero- and longitudinal-field muon spin relaxation

“…As for x = 0.20, the increase and the saturation of the muon-spin-relaxation rate were observed at low temperatures, which is possibly a precursor to the Bose-glass phase at T =0. 23,24 These results are consistent with the theoretical and experimental predictions that the Bose-glass phase is expected to appear for x Ͼ 0. [25][26][27][28][29][30] In the case of x = 0.44 and 0.58, the increase of is observed, which suggests the slowing down of the frequency of the Cu 3d spin fluctuations toward a spin frozen state below 20 mK in contrast to the predicted Bose-glass phase, and the rootexponential-like behavior of the time spectrum indicates that the origin of the relaxation is possibly the spatially fixed fluctuating dilute moments.…”

The Effect of Randomness on the Quantum Spin System Tl1-xKxCuCl3 with x=0.44 Studied by the Zero-Field Muon-Spin-Relaxation (ZF-µSR) Method

“…36,37) These results are consistent with the theoretical prediction that the Bose-glass phase is expected to appear for x > 0. However, it is not yet known whether or not another ground state apart from the Bose-glass phase and the gapped state appears when the randomness is enhanced with increasing the concentration of x in the system.…”

Muon spin relaxation detection of the soft mode toward the exotic magnetic ground state in the bond-disordered quantum spin systemIPA-Cu(Cl0.35Br0.65Goto1, Suzuki2, Kanada3 et al. 2008Phys. Rev. B272140View full textAdd to dashboardCite

“…The evidence of the localization has actually been reported in the other disordered quantum spin system ͑Tl, K͒ CuCl 3 , which is believed to have the ground state of the Bose glass, [8][9][10] as a discrepancy between the temperature dependence of the uniform and the local magnetization-the latter of which is probed by NMR shift. 11 In the present case, our tentative NMR study shows a different temperature dependence between NMR shift and the uniform susceptibility. This also supports the Bose-glass picture.…”

“…6,7 A disordered spin system is one of the candidates that bear the ground state of the Bose glass. Although possibility of the experimental detection of the Bose-glass phase by either macroscopic [8][9][10] or microscopic 11,12 probes was repeatedly suggested in the solid solution of two different spin-gap systems, details still remain obscure.…”