Local magnetic structure due to inhomogeneity of interaction in S=1/2 antiferromagnetic chains

We study the magnetic properties of S = 1/2 antiferromagnetic Heisenberg ch ains with inhomogeneity of interaction. Using a quantum Monte Carlo method and an exact diagonalization method, we study me bond/impurity effect in th e uniform S = 1/2 chain. Here "bond impurity" means a bond with a strength different from those in the bulk. In particular, by calculating the local m agnetization, the local susceptibility, and the local field susceptibility, the temperature dependence of local magnetic structures induced by bond im purities is investigated We also investigate the force acting between bond impurities and find that the force is attractive.