Influence of the compacting pressure on the transport properties of CrO₂ at low temperatures

The influence of pressure on the magnetotransport properties of CrO₂ samples at low temperatures has been studied in this paper. The X-ray diffraction patterns of the samples show that the relative intensity of (110) peak increases with increasing pressure, which implies that pressure has the orientation effect on the CrO₂ needle-shaped nanoparticles. At low temperatures, the resistance and magnetoresistance of CrO₂ samples decrease with the increase of pressure. The experimental results suggest that at low temperatures, the conductance of the sample shows the typical characteristic of intergranular tunneling. Δ decreases with increasing pressure and magnetic field; and furthermore, the range of change of Δ with the magnetic field is related to the compacting pressure. The higher the compacting pressure, the smaller the variation of Δ with the magnetic field. These changes can be attributed to the adjustment of pressure on the intergranular tunnel barrier.