High-field ESR study of the dimerized-incommensurate phase transition in the spin-Peierls compound CuGeO 3

Abstract

The dimerized-incommensurate phase transition in the spin-Peierls compound CuGeO 3 is probed using the tunable-frequency high-resolution electron spin resonance technique in magnetic fields up to 17 T . A field-induced development of the soliton-like incommensurate superstructure is clearly indicated as a pronounced increase of the magnon spin resonance linewidth Δ B, with a Δ B max at B c ∼13.8 T . The anomaly is explained in terms of the magnon–soliton scattering and suggests that the soliton-like phase exists close to the boundary of the dimerized-incommensurate phase transition. In addition, magnetic excitation spectra in 0.8% Si-doped CuGeO 3 are studied. Some features of the high-field high-resolution tunable-frequency ESR facility recently developed in Tallahassee are presented.