Investigation of Linear and Alternating Quasi-one-dimensional Spin Chains in Hambergite Single Crystal by Means of 1H NMR

1 H NMR in quasi-one-dimensional spin chains is investigated experimentally on the single crystal of hambergite, Be 2 BO 3 OH. The orientations at which the change of the spin chain direction with respect to the external magnetic field results in the occurrence of homogeneous and alternating chains are found. The dependence of the lineshape on the orientation in magnetic field for alternating spin chain is obtained and the data are analyzed using a simple model taking into the dipolar interactions with the nearest neighbors. The analogies with the lineshapes typical for spin systems with a small number of spin and known linear spin chain are discussed.