Effect of disorder on the linear and nonlinear magnetic susceptibilities of two manganeseporphryin-based magnets

We analyze the effects of disorder on the magnetic properties of two manganeseporphyrins, [MnTPP][TCNE] •. x(o-DCB) and [MnTPP][TCNE] . • y(o-Xy) and (TPP=meso-tetraphenylporphyrinato, TCNE=tetracyanoethylene, o-Xy=o-xylene, o-DCB=o-dichlorobenzene, x<_3,y<_1). We present data for the in- and out-of-phase ac susceptibility and obtain the distribution of relaxation times using Cole-Cole analysis. The frequency dependence of the linear susceptibility suggests cluster glasslike behavior. The peak in the second harmonic of the ac susceptibility indicates the presence of a spontaneous magnetic moment. We propose that the unusual magnetic properties of these compounds reflect one-dimensional ferrimagnetic clusters interacting weakly through dipole-dipole interactions to form three-dimensional domains. © 1997 American Institute of Physics. [S0021-8979(97)34408-9]