  Basal plane resistivity of expanded graphite was studied under simultaneous
influence of hydrostatic pressure up to 1.8 GPa and magnetic field 0.8 T in the
77-300 K temperature region. Magnetic field induces negative magnetoresistance
in the sample within all temperature and pressure range studied. A change in
resistivity of the sample under maximum pressure reaches 80%. Significant
change in resistivity dependence on temperature under the pressure of 0.6 GPa
suggests for ordering transition in the sample studied. Negative
magnetoresistance in the graphite reaches about 15% at 0.6 GPa. Magnetic field
acts in the same way as pressure and potentiates the transition formation and
further magnetoresistance dynamics. The effects observed are mostly of elastic
character according to resistivity of the unloaded sample.
