(BEDT-TTF)6(CUX2Y2)2 (X=BR, Y=CL OR BR) - ELECTRICAL-TRANSPORT PROPERTIES UNDER PRESSURE AND MAGNETIC-PROPERTIES

We report the electrical transport properties of the titled compounds in the pressure range 1 bar to 24kbar and temperature range 2-320K as well as the magnetic properties at ambient pressure. The conductivity of these two materials shows the largest pressure change known in the organic conductors field; the conductivity increases 500 times on goin g from 1bar to 24kbar. The materials become semimetallic above 7kbar. The phase transition observed at 60K at ambient pressure increases to a maximum 110 K at approximately 6kbar before decreasing linearly to 8 0K at 20kbar. The results are correlated to the crystal and electronic structures.