Electron Spin Resonance of Spin-Peierls Material CuGeO₃

Abstract

Magnetization and submillimeter wave ESR measurements have been performed on single crystals of CuGeO 3 using a pulsed high magnetic field. Magnetization jumps are observed at 12.8, 12.5 and 13.5 T for a -, b - and c -axes, respectively, at 4.2 K. The temperature dependences of the linewidth and the integrated intensity of the ESR signal are discussed in connection with the conventional spin-Peierls systems, and the excitation gap against the magnetic field is estimated when the field is applied along the a -axis. ESR has been observed in the magnetic phase above the critical field H c and the g -values have different values from those in the spin-Peierls phase. The origin of this difference is discussed.