Long-range order in the one-dimensional cobalt(II)-radical coordination polymer magnet probed by muon-spin rotation and relaxation.

A long-range-ordered state of CoBPNN was characterized by muSR. The temperature at the depolarization rate divergence (40 K) is defined as a magnetic transition temperature (T(N)). The phase is unique below T(N), but gradual freezing of the domain-wall motion finally leads to the magnetically hard character.

Giant coercivity in a one-dimensional cobalt-radical coordination magnet.

A metal-radical polymer [Co(hfac)2.BPNN] showed a very large coercive field of 52 kOe (4.1 MA m-1) at 6 K, indicating that it is the hardest magnet ever reported. Above 10 K, a soft character appeared, owing to the fast dynamics of magnetization reorientation.