Spin-lattice interaction in the quasi-one-dimensional helimagnet LiCu2O2.
The field dependence of the electron spin resonance in a helimagnet LiCu2O2 was investigated for the first time. In the paramagnetic state, a broad resonance line was observed corresponding to a g factor of 2.3. In the critical regime, around the paramagnetic to helimagnetic phase transition the resonance broadens and shifts to higher frequencies. A narrow signal is recovered at a low temperature, corresponding to a spin gap of 1.4 meV in zero field. A comprehensive model of the magnons is presented, using exchange parameters from neutron scattering [T. Masuda Phys. Rev. B 72, 014405 (2005)10.1103/PhysRevB.72.014405] and the spin anisotropy determined here. The role of the quantum fluctuations is discussed.
Mihály
László
L
Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA.
Dóra
Balázs
B
Ványolos
András
A
Berger
Helmuth
H
Forró
László
L