We consider the effect of doping on the magnetic order in quasi
one-dimensional (1D) antiferromagnets. First the detailed magnetic response of
finite spin-1/2 chains in the presence of a staggered field is determined,
which by itself shows an interesting crossover as function of length and field
strength. We can then understand the ordering by including an effective
coupling between the chains, which results in a Neel ordered phase at low
temperatures, but with a broad distribution of magnetic moments that has to be
determined self-consistently.Comment: 2 pages, 1 figure. Latest pdf-file is available at
http://www.physik.uni-kl.de/eggert/papers/magorder.pd