Partitioning the Two-Leg Spin Ladder in Ba₂Cu_1 -  Zn TeO₆: From Magnetic Order through Spin-Freezing to Paramagnetism

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Magnetism

Background:

• Barium copper telluride (Ba₂CuTeO₆) exhibits a two-leg spin ladder structure with Cu²⁺ cations near a quantum critical point.
• Chemical substitutions in Ba₂CuTeO₆ can significantly alter its magnetic properties.

Purpose of the Study:

• Investigate the impact of non-magnetic Zn²⁺ substitution on the Cu²⁺ spin ladders in Ba₂CuTeO₆.
• Characterize the resulting magnetic behavior and understand the role of chemical disorder.

Main Methods:

• Synthesis of Ba₂Cu_1-xZn_xTeO₆ solid solutions (0 ≤ x ≤ 0.6).
• Bulk thermodynamic measurements.
• Local muon magnetic characterization.

Main Results:

• Zn²⁺ impurities partition the Cu²⁺ spin ladders into finite-sized clusters.
• Magnetic behavior transitions from long-range order to spin-freezing between x = 0.1 and x = 0.2, consistent with percolation theory.
• Above a critical cluster size, the material exhibits paramagnetic behavior.

Conclusions:

• Zn²⁺ substitution provides controlled tuning of magnetic disorder in Ba₂CuTeO₆.
• Ba₂Cu_1-xZn_xTeO₆ serves as an ideal model system for studying defects and segmentation effects in low-dimensional quantum magnets.
• This work highlights the importance of chemical substitution in manipulating quantum magnetic phenomena.