Magnetization of undoped 2-leg S = 1/2 spin ladders in La4Sr10Cu24O41
  Magnetization data of single crystalline La4Sr10Cu24O41 are presented. In this compound, doped spin chains and undoped spin ladders are realized. The magnetization, at low temperatures, is governed by the chain subsystem with a finite interchain coupling which leads to short range antiferromagnetic spin correlations. At higher temperatures, the response of the chains can be estimated in terms of a Curie-Weiss law. For the ladders, we apply the low-temperature approximation for a S=1/2 2-leg spin ladder by Troyer et al. 
R. Klingeler, I. Hellmann, P. Ribeiro, C. Hess, B. Buechner