  The magnetic properties of the one dimensional (1D) monatomic chain of Co
reported in a previous experimental work are investigated by a classical Monte
Carlo simulation based on the anisotropic Heisenberg model. In our simulation,
the effect of the on-site uniaxial anisotropy, Ku, on each individual Co atom
and the nearest neighbour exchange interaction, J, are accounted for. The
normalized coercivity HC(T)/HC(TCL) is found to show a universal behaviour,
HC(T)/HC(TCL) = h0(e^{TB/T}-e) in the temperature interval, TCL < T < TBCal,
arising from the thermal activation effect. In the above expression, h0 is a
constant, TBCal is the blocking temperature determined by the calculation, and
TCL is the temperature above which the classical Monte Carlo simulation gives a
good description on the investigated system. The present simulation has
reproduced the experimental features, including the temperature dependent
coercivity, HC(T), and the angular dependence of the remanent magnetization,
MR(phi,theta), upon the relative orientation (phi,theta) of the applied field
H. In addition, the calculation reveals that the ferromagnetic-like open
hysteresis loop is a result of a slow dynamical process at T < TBCal. The
dependence of the dynamical TBCal on the field sweeping rate R, the on-site
anisotropy constant Ku, and the number of atoms in the atomic chain, N, has
been investigated in detail.
