Conducting Molecular Magnets Based on TTF-Derivatives

Abstract

The crystal structures, electronic and magnetic properties of conducting molecular magnets developed in our group are reviewed. (DMET) 2FeBr 4 is composed of alternating stacks of quasi-one-dimensional (1D) donor sheets and square lattice magnetic anion sheets. This salt undergoes an SDW transition of the donor layer at 40 K and an antiferromagnetic transition of Fe 3+ spins on the anion layer at 3.7 K. The one-to-one correspondence of the anomalies appearing on the magnetization curves with those on the magnetoresistance supports the presence of the π– d interaction. (EDO–TTFI 2) 2[ M( mnt) 2] ( M=Ni,Pt) consists of 1D chains of conducting donors and magnetic anions aligned in parallel. These salts show metallic conductivity accompanied with a metal–insulator transition around 90 K. Localized spins on the anions behave as a 1D ferromagnet, whose origin is explained by McConnell's first model. The properties of related materials, (EDTDM) 2FeBr 4, (EDS–TTF) 2FeBr 4 and (EDO–TTFBr 2) 2FeBr 4, are also presented.