Molecular magnetic semiconductors formed by cationic and anionic networks: (ET)2Mn[N(CN)2]3 and (ET)2CuMn[N(CN)2]4

Abstract

Crystals of (ET)₂Mn[N(CN)₂]₃ (1) and (ET)₂CuMn[N(CN)₂]₄ (2) with mono- and first bimetal dicyanamide anions were obtained and their structure, conducting and magnetic properties were investigated. The structure of 2 is not typical for ET radical cation salts and is characterized by the presence of a 3D polymeric anion built into the ET radical cation layers. The crystals of 1 exhibit a semiconducting behavior of conductivity and 2 undergoes a semiconductor I–semiconductor II phase transition at 295–291 K, which is specified by a jump of resistivity and the appearance of a hysteresis in the R(T) curves. The phase transition is accompanied by changes in the charge state of the ET molecules and intermolecular interactions in the crystal. Antiferromagnetic correlations of spins associated with anionic subsystems were found in both salts at temperatures lower than 25 K. Antiferromagnetic ordering in 1 has a long-range character. The effect of the spin frustrated state of localized spins on conducting electrons of ET subsystem was found in 1.