Metal-Insulator-Transition And Metallic Conductivity Reentrance In The New Organic Metal (Nhme3)[Ni(Dmit)2]2 - High-Field Magnetoresistance

We present here the first data on the electron transport properties of (NHMe3)[Ni(dmit)2]2, a new organic conductor. At room temperature, the samples exhibit a low resistivity of a few 10(-3) OMEGA-cm. Lowering the temperature we observe first a weakly metallic behaviour down to 100 K followed by a metal-insulator transition and then, around 10 K, by a reentrance of the metallic conductivity. At low temperature and under a high magnetic field up to 30 T a large negative magnetoresistance appears. The resistivity and magnetoresistance data could indicate we are dealing with localized carriers.