EFFECT OF DISORDER ON THE LINEAR AND NONLINEAR MAGNETIC-SUSCEPTIBILITIES OF 2 MANGANESEPORPHYRIN-BASED MAGNETS

We analyze the effects of disorder on the magnetic properties of two m anganeseporphyrins, [MnTPP][TCNE] . x(o-DCB) and [MnTPP][TCNE] . y(o-X y) and (TPP=meso-tetraphenyl-porphyrinato, TCNE=tetracyanoethylene, o- Xy=o-xylene, o-DCB=o-dichlorobenzene, x less than or equal to 3, y les s than or equal to 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 susceptibil ity suggests cluster glasslike behavior. The peak in the second harmon ic of the ac susceptibility indicates the presence of a spontaneous ma gnetic moment. We propose that the unusual magnetic properties of thes e compounds reflect one-dimensional ferrimagnetic clusters interacting weakly through dipole-dipole interactions to form three-dimensional d omains. (C) 1997 American Institute of Physics.