Sidebands on EPR Lines in Low-Dimensional Systems

Abstract

Measurements of a half-field transition in the EPR spectrum are reported in the one-dimensional Heisenberg magnet (CH₃)₄NMnCl₃ (TMMC), and compared with a theory developed here. The theory accounts in a satisfactory way for the observed anisotropic feature. The results reveal that the appearance of the subsidiary resonance provides a direct evidence of the long-time tail of spin correlation functions in low-dimensional systems.