Band structure and physical properties of an organic conductor (BEDT-TTF)4Cu(C2O4)2

Update 1 of: Calorimetric Investigation of Phase Transitions Occurring in Molecule-Based Magnets

“…An AF transition due to the d-electrons in the Cu­(II) was found at 7.5 K by magnetization measurements, but the thermodynamic study to discuss π–d interaction is not performed at present. A charge transfer complex consisting of BEDT-TTF and dioxalatocuprate with a chemical formula of (BEDT-TTF) 4 Cu­(C 2 O 4 ) was studied by Wang et al by a.c. heat capacity. They observed a sharp peak at 262 K and broad peak around 170 K, both attributed to the structural changes.…”

Magnetic TTF-Based Charge-Transfer Complexes

“…In insulating materials, the interaction originates from a superexchange interaction, in contrast to the case of metallic materials, which are subjected to conduction−electron-mediated interactions, as discussed in section 2. In developing such π−d composite systems and enhancing their π−d interaction, much effort has been made so far by employing mainly transition metal halides as counteranions, − leading to a variety of π−d composite magnets.…”

“…Therefore, intentional designing of a molecular arrangement with the cooperation of donor π-electrons is expected to result in a large variety of d-electron-based molecular magnets having different dimensionality and magnetic features such as antiferromagnetism, ferromagnetism, weak ferromagnetism, and so forth. There are many examples of π-electron-mediated superexchange interaction systems: (TMTSF)FeCl 4 , (TMTTF)FeCl 4 , (BEDT-TTF) 3 (MnCl 4 ) 2 , (BEDT-TTF) 4 Cu(C 2 O 4 ) 2 , (C 1 TET-TTF)CuBr 4 , (C 1 TET-TTF)FeX 4 (X = Cl, Br), − and so forth. Here, we discuss the magnetism of (C 1 TET-TTF)FeX 4 (X = Cl, Br), which are characterized by a triangle-based ladder lattice with weak ferromagnetism.…”