The Hall effect in the organic conductor TTF-TCNQ: choice of geometry for accurate measurements of a highly anisotropic system.

We have measured the Hall effect on recently synthesized single crystals of the quasi-one-dimensional organic conductor TTF?TCNQ (tetrathiafulvalene?tetracyanoquinodimethane), a well known charge transfer complex that has two kinds of conductive stacks: the donor (TTF) and the acceptor (TCNQ) chains. The measurements were performed in the temperature interval 30?K? ?150?K), implying that there is no dominance of either the TTF or the TCNQ chain. At lower temperatures our measurements clearly prove that all three phase transitions of TTF?TCNQ could be identified from Hall effect measurements.