title: Ferromagnetic ordering of Fe(III) d spins of FeBr4- ions in (ethylenedithiotetrathiafulvalenothioquinone-ethylenedithio-1,3-dithiolemethide) x FeBr4.
abstract: The 1:1 salt of a new donor molecule, ethylenedithiotetrathiafulvalenothioquinone-ethylenedithio-1,3-dithiolemethide (1), with FeBr4- ion, 1 x FeBr4, was prepared and found to exhibit a room-temperature electrical conductivity of 4 x 10(-2) S cm(-1) and semiconducting behavior with an activation energy of 170 meV. The paramagnetic susceptibility obeyed the Curie-Weiss law with a Curie constant of 4.42 emu K mol(-1) and a Weiss temperature of +3.4 K, and below 15 K, this short-range ferromagnetic interaction increasingly extended to two- and/or three-dimensional interactions, eventually giving rise to a ferromagnetic ordering, whose temperature (TC) was determined to be 1.8 +/- 0.2 K using a resonant circuit method. The magnetic field dependence of magnetization showed that the saturation of magnetization was accomplished at ca. 60 kOe and the saturated value was ca. 5 microB, which is very close to the value obtained only due to Fe(III) (S = 5/2) d spins of one FeBr4- ion.
authors.affiliation: Research Institute for Advanced Science and Technology, Osaka Prefecture University, Osaka 599-8570, Japan.
authors.forename: Mingxing
authors.initials: M
authors.lastname: Wang
authors.forename: Hideki
authors.initials: H
authors.lastname: Fujiwara
authors.forename: Toyonari
authors.initials: T
authors.lastname: Sugimoto
authors.forename: Satoru
authors.initials: S
authors.lastname: Noguchi
authors.forename: Takekazu
authors.initials: T
authors.lastname: Ishida