Effect of pressure on the electric transport properties of carbon-doped

We report about the influence of external pressure on the electrical resistivity of EuB5.99C0.01, the compound believed to be intrinsically inhomogeneous due to fluctuations of carbon content. Our results show that the low-temperature resistivity maximum shifts to a lower temperature with applied pressure, opposite to the behavior reported for stoichiometric EuB6. The origin of such a qualitative difference we associate with the increasing volume fraction of the phase that is not compatible with ferromagnetic ordering (originating in regions with relatively higher carbon concentration) with increasing pressure. Our results support a recent proposition of Batkova et al. (2008) [12] that carbon-rich regions strongly influence magnetotransport properties of carbon-doped EuB6, such as they play a role of “spacers”, which prevent the percolation of a ferromagnetic phase.