NMR study of low dimensional spin system Cu2(PO3)2CH2

Abstract: The low dimensional spin system Cu2(PO3)2CH2 has been investigated by means of NMR spectroscopy. 31P NMR measurements were performed in the temperature range 2–200K. Above T c ∼10K the 31P NMR spectra consist of two distinct peaks which coincides with two non equivalent crystallographic P sites. Below 10K a convergence of both peaks is observed. The chemical shift tends to approach the constant value at T →0 evidencing for the gap formation in the magnetic excitation spectrum. These results are analyzed in frames of both alternating spin chain and dimer models. [Copyright &y& Elsevier]