Unusual transport properties in the orbitally-ordered system Lu$_{2}$V$_{2}$O$_{7}$

DC susceptibility ($\chi )$, AC and DC resistivity ($\rho )$, specific heat ($C_{p})$, and thermoconductivity ($k)$ measurements on single crystalline Lu$_{2}$V$_{2}$O$_{7}$ with the pyrochlore structure reveal two transitions: (1) a short-range magnetic ordering transition at $T_{s}$ = 175 K, which is identified by the slope change of 1/ $\chi $ and 1/$k$, an anomaly in the AC resistivity, and a change in the activation energy (2) an orbital ordering transition at $T_{o}$ = 70 K, which is confirmed by the sharp transition on $\chi $, $k$, and $C_{p}$. At $T_{o}$, the resistivity shows an unusual insulator-metal transition which will be discussed in relation to the orbital ordering transition.