Partitioning the Two-Leg Spin Ladder in Ba(2)Cu(1 – x)Zn(x)TeO(6): From Magnetic Order through Spin-Freezing to Paramagnetism

[Image: see text] Ba(2)CuTeO(6) has attracted significant attention as it contains a two-leg spin ladder of Cu(2+) cations that lies in close proximity to a quantum critical point. Recently, Ba(2)CuTeO(6) has been shown to accommodate chemical substitutions, which can significantly tune its magnetic behavior. Here, we investigate the effects of substitution for non-magnetic Zn(2+) impurities at the Cu(2+) site, partitioning the spin ladders. Results from bulk thermodynamic and local muon magnetic characterization on the Ba(2)Cu(1 – x)Zn(x)TeO(6) solid solution (0 ≤ x ≤ 0.6) indicate that Zn(2+) partitions the Cu(2+) spin ladders into clusters and can be considered using the percolation theory. As the average cluster size decreases with increasing Zn(2+) substitution, there is an evolving transition from long-range order to spin-freezing as the critical cluster size is reached between x = 0.1 to x = 0.2, beyond which the behavior became paramagnetic. This demonstrates well-controlled tuning of the magnetic disorder, which is highly topical across a range of low-dimensional Cu(2+)-based materials. However, in many of these cases, the chemical disorder is also relatively strong in contrast to Ba(2)CuTeO(6) and its derivatives. Therefore, Ba(2)Cu(1 – x)Zn(x)TeO(6) provides an ideal model system for isolating the effect of defects and segmentation in low-dimensional quantum magnets.