Magnetism study on a triangular lattice antiferromagnet Cu₂(OH)₃Br.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Magnetism

Background:

• Cu$_{2}$(OH)$_{3}$Br exhibits a triangular lattice structure, a common motif in frustrated magnetic systems.
• Understanding the magnetic properties of low-dimensional quantum materials is crucial for developing new electronic devices.

Purpose of the Study:

• To investigate the magnetic properties of Cu$_{2}$(OH)$_{3}$Br single crystals.
• To elucidate the nature of the magnetic ordering and field-induced transitions.

Main Methods:

• Magnetic susceptibility measurements
• Pulsed-field magnetization experiments
• Specific heat measurements

Main Results:

• Two inequivalent Cu$^{2+}$ sites were identified, both ordering antiferromagnetically (AFM) below a critical temperature.
• An anisotropy crossover from Heisenberg to XY behavior was observed below 7.5 K.
• A spin-flop transition occurred between 4.9 T and 5.3 T in an in-plane magnetic field, with magnetization reaching only half saturation even at 30 T.
• The magnetic specific heat data supported a model of two gapped AFM contributions.

Conclusions:

• The complex magnetization behavior is attributed to the individual reorientation of inequivalent Cu$^{2+}$ spins.
• The strong AFM coupling among some Cu spins prevents full saturation even at high magnetic fields.
• The findings provide insights into the magnetic interactions in triangular lattice systems.