Field induced long-range-ordering in an S=1 quasi-one-dimensional   Heisenberg antiferromagnet
  We have measured the heat capacity and magnetization of the spin one one-dimensional Heisenberg antiferromagnet NDMAP and constructed a magnetic field versus temperature phase diagram. We found a field induced long-range magnetic ordering. We have been successful in explaining the phase diagram theoretically. 
Z. Honda, K. Katsumata, Y. Nishiyama and I. Harada