Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 25: Correlated Electrons - Poster Session
TT 25.23: Poster
Mittwoch, 29. März 2006, 14:30–18:30, P1
Spatial Localization Behavior in the Two-Dimensional Inherent Conducting Polymer {(CH3)0.92ReO3}∞ — •E.–W. Scheidt1, R. Miller1, G. Eickerling1, Ch. Helbig1, F. Mayr1, R. Herrmann1, W. Scherer1, and H.–A. Krug von Nidda2 — 1Chemische Physik und Materialwissenschaften, Universität Augsburg, 86159 Augsburg, Germany — 2EP V, Elektronische Korrelationen und Magnetismus, Institut für Physik, Universität Augsburg, 86159 Augsburg, Germany
Polymeric methyltrioxorhenium, (CH3)0.92ReO3 (poly-MTO), is the first member of a new class of inherent conductive organometallic hybrids and represents a prototype for a purely two-dimensional system, confirmed by X-ray- and IR-studies as well as by specific-heat and resistivity measurements. Below a characteristic temperature the resistivity changes from metallic to insulating behavior, where in the latter a positive magnetoresistance is observed. These properties are intensified by intercalation studies of poly-MTO with donor and acceptor molecules leading to a preliminary phase diagram. The increasing temperature range of the insulating regime is accompanied by an increasing amount of localized magnetic moments at the ReVI (d1)-ions as revealed by susceptibility and magnetization measurements and ascertained by ESR studies. Magnetic field dependent susceptibility measurements also clarify the role of the magnetic field as a tuning parameter for localization. This may be the reason for the positive magnetoresistance in these systems. This scenario is also corroborated by the magnetic field dependent electrical field gradient Vzz determined from the specific heat contribution of the quadrupole moments and confirmed by DFT calculations.