High field magnetic resonant properties of beta'-(ET)2SF5CF2SO3

A systematic electron spin resonance (ESR) investigation of the low temperature regime for the (ET)2SF5CF2SO3 system was performed in the frequency range of ~200-700 GHz, using backward wave oscillator sources, and at fields up to 25 T. Newly acquired access to the high frequency and fields shows experimental ESR results in agreement with the nuclear magnetic resonance (NMR) investigation, revealing evidence that the transition seen at 20 K is not of conventional spin-Peierls order. A significant change of the spin resonance spectrum in beta'-(ET)2SF5CF2SO3 at low temperatures, indicates a transition into a three-dimensional-antiferromagnetic (3D AFM) phase.Comment: 4 pages, 7 figures, minor grammatical change

Spin transition in [Fe(PM-BiA)(2)(NCS)(2)] studied by the electron paramagnetic resonance of the Mn2+ ion

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Physical properties of the DMt-TTF salts: a new series presenting antiferromagnetic ground states.

The conducting and magnetic properties of three salts of the DMtTTF series are described. Low temperature antiferromagnetic ground states are found for the three compounds. Depending on the anions the crystal organisation is either triclinic (as for the TMTTF salts) or monoclinic. As expected, the position of the magnetic axis is correlated to the crystal symmetry. Finally the origin of the magnetic phase is discussed using the same theoretical framework as for the related TMTTF salts.On décrit les propriétés conductrices et magnétiques de trois composés de la série des sels de DMtTTF. On observe pour chacun d' eux un état antiferromagnétique basse température. Selon l'anion, l'organisation cristalline est, soit triclinique (similaire à celle des sels de TMTTF), soit monoclinique. Comme attendu, la position des axes magnétiques est fonction de la symétrie cristalline. Finallement, l'origine de la phase magnétique est discutée au moyen des descriptions théoriques déjà utilisées pour des composés voisins, les sels de TMTTF

Temperature and pressure dependencies of the crystal structure of the organic superconductor (TMTSF)

The crystal structure of (TMTSF)2ClO4 has been determined at (7 K, 1 bar) and at (7 K, 5 kbar) with a high accuracy. For the latter, low temperature and pressure were applied simultaneously using a X-ray diffraction instrumentation designed in our laboratory, these results are the first for molecular compounds. The effects of lowering the temperature are not the same as those produced by increasing the pressure. At (7 K, 1 bar) the anion ordering which occurs in this compound, and which is characterised by the appearance of $b^*/2$ superlattice reflections, is well observed. This anion ordering leads to the presence of two independent stacks of TMTSF cations which is the only case found in the Bechgaard salts family. The comparison of the low temperature crystal structures under atmospheric pressure and at 5 kbar shows that the centres of mass are nearly the same, independent of the pressure: the interchain interactions do not depend on the doubling of the unit cell. Under pressure, the ordering (0, 1/2, 0) does not occur at any temperature. These structural data are confirmed by the quantum chemical calculations which show that the difference in the site energy of the two independent cations is 100 meV

Spin transition in [Fe(PM-BiA)(2)(NCS)(2)] studied by the electron paramagnetic resonance of the Mn2+ ion

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Spin transition in [Fe(PM-BiA)(2)(NCS)(2)] studied by the electron paramagnetic resonance of the Mn2+ ion

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A linear, four-spin Mn(II)-nitronyl-nitroxide-substituted phosphine oxide system exhibiting both antiferro- and ferromagnetic interactions

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