  Quantum correlation in two-qubit spin models is investigated by use of
measurement-induced disturbance [S. Luo, Phys. Rev. A, 77(2008) 022301]. Its
dependences on external magnetic field, spin-spin coupling, and
Dzyaloshinski-Moriya (DM) interactions are presented in detail. We also compare
measurement-induced disturbance and thermal entanglement in spin models and
illustrate their different characteristics.
