Positive muons in spin-crossover complex [Fe(NCS)2(phen)2]

Diamagnetic muon species in a spin-crossover complex diisothiocyanatobisphenanthrolineiron(II) were investigated: two species with different spin relaxation functions and rates were observed over the range from 21 to 293 K. The sum of their yields changed at about the spin transition temperature of the complex, where the spin state of the complex changes from paramagnetic to diamagnetic when it is cooled down across the temperature. The results suggest that paramagnetic muon species could exhibit diamagnetic muon-like SR signals in paramagnetic environment.