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Regular version of the site

Article

Electron spin resonance in a model S=1/2 chain antiferromagnet with a uniform Dzyaloshinskii-Moriya interaction

Smirnov A., Soldatov T. A., Povarov K. Y., Hälg M., Lorenz W. E., Zheludev A.

The electron spin resonance spectrum of a quasi-1D S=1/2 antiferromagnet K2CuSO4Br2 was found to demonstrate an energy gap and a doublet of resonance lines in a wide temperature range between the Curie-Weiss and Neèl temperatures. This type of magnetic resonance absorption corresponds well to the two-spinon continuum of excitations in S=1/2 antiferromagnetic spin chain with a uniform Dzyaloshinskii-Moriya interaction between the magnetic ions. A resonance mode of paramagnetic defects demonstrating strongly anisotropic behavior due to interaction with spinon excitations in the main matrix is also observed.