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

TL;DR

This study uses Cu-NMR to investigate the disordered quantum spin magnet Tl1-xKxCuCl3, revealing inhomogeneous hyperfine fields and evidence for a Bose-glass ground state in the presence of disorder and magnetic field.

Contribution

It provides experimental evidence for the Bose-glass phase in a disordered quantum spin system using NMR techniques.

Findings

Inhomogeneous hyperfine fields at high fields due to magnetic order

Saturation in relaxation rate at low fields indicating Bose-glass phase

Observation of disordered spin-gap system behavior

Abstract

Cu-NMR study has been performed on the disordered spin-gap system Tl1-xKxCuCl3 In the high-field H > HC=\Delta/\mu_B, where \Delta 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 1/T1 was observed at low temperatures, indicating existence of the magnetic ground state proposed to be Bose-glass phase by Fisher.