Exchange splitting inCuGeO3under ultrahigh magnetic fields

Abstract
Electron paramagnetic resonance has been observed on CuGeO3 in ultrahigh magnetic fields up to 180 T. The distinct exchange splitting is found between the two inequivalent Cu2+ sites along the b axis. Analyzing the data on the basis of a simple two-spin model, we evaluated the interchain exchange coupling Jb as ∼0.9 meV. This value is a little smaller than Jb1.0meV obtained by neutron-scattering experiments.