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Singlet ground state of the quantum antiferromagnet Ba(3)CuSb(2)O(9)
J A Quilliam1, F Bert, E Kermarrec
1Laboratoire de Physique des Solides, Université Paris-Sud 11, UMR CNRS 8502, 91405 Orsay, France.
Physical Review Letters
|September 26, 2012
Summary
This study on the honeycomb lattice antiferromagnet Ba(3)CuSb(2)O(9) found no spin freezing in its ground state. Magnetic excitations in the material are gapped, as indicated by NMR measurements.
Area of Science:
- Condensed Matter Physics
- Quantum Magnetism
- Materials Science
Background:
- The honeycomb lattice antiferromagnet Ba(3)CuSb(2)O(9) is a material of interest for studying exotic magnetic phenomena.
- Understanding the magnetic ground state and elementary excitations is crucial for characterizing such materials.
Purpose of the Study:
- To investigate the magnetic properties of Ba(3)CuSb(2)O(9) at low temperatures.
- To determine the presence or absence of spin freezing and characterize magnetic excitations.
Main Methods:
- Muon spin relaxation (μSR) measurements were performed in a zero magnetic field down to 20 mK.
- Antimony Nuclear Magnetic Resonance (Sb NMR) spectroscopy was utilized to probe the intrinsic magnetic susceptibility and spin-lattice relaxation rate.
Main Results:
- Muon spin relaxation measurements unequivocally demonstrated the absence of spin freezing in the ground state.
- Sb NMR revealed a peak in magnetic susceptibility around 55 K, decreasing to zero at low temperatures.
- The spin-lattice relaxation rate exhibited two distinct energy scales and a field-dependent crossover, indicative of gapped magnetic excitations.
Conclusions:
- Ba(3)CuSb(2)O(9) does not exhibit spin freezing in its ground state.
- The material possesses gapped magnetic excitations, a key feature in certain quantum magnetic systems.
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