Abstract
ESR measurements have been performed on KCuCl3 and TlCuCl3 in the frequency range up to 762 GHz and field range up to 30 T at helium temperatures. The exchange network in the present systems is described as an S = 1/2 Heisenberg spin ladder along the a-axis with an additional diagonal interaction. Both compounds have a singlet ground state with an excitation gap. In KCuCl3, two kinds of transitions are observed between the ground state and the excited triplet states. They correspond to the excitations at Q = (1,0,1) and (0.5,0,1) with the excitation energies Δ ≈ 640 and 1080 GHz, respectively. When the external field is increased, the frequency of the lowest branch with the zero-field gap Δ ≈ 640 GHz decreases linearly with a tendency toward zero at Hc ≈ 22 T. In TlCuCl3, a transition from the singlet ground state to the excited triplet state is observed. The zero-field gap is determined as Δ ≈ 160 GHz.
Original language | English |
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Pages (from-to) | 545-548 |
Number of pages | 4 |
Journal | Physica B: Condensed Matter |
Volume | 246-247 |
DOIs | |
Publication status | Published - May 29 1998 |
Keywords
- Double spin chain
- ESR
- Excitation gap
- High magnetic field
- KCuCl
- Singlet ground state
- TlCuCl
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering