Negative magnetoresistance dynamics in expanded graphite under hydrostatic pressure up to 1.8 GPa

TL;DR

This study investigates how hydrostatic pressure and magnetic fields influence the resistivity and magnetoresistance of expanded graphite, revealing pressure-induced transitions and elastic effects up to 1.8 GPa.

Contribution

It provides new insights into the pressure and magnetic field effects on resistivity and magnetoresistance in expanded graphite, highlighting transition phenomena and elastic behavior.

Findings

Magnetic field induces negative magnetoresistance across all tested conditions.

Resistivity changes up to 80% under maximum pressure.

Significant resistivity dependence change at 0.6 GPa indicating an ordering transition.

Abstract

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.