Low-temperature magnetoresistance in untwinned CaRuO₃ films

CaRuO₃ is a paramagnetic metal and since its low-temperature resistivity is described by ρ = ρ₀ + AT^α with α ∼ 1.5, it is also considered a non-Fermi liquid (NFL) metal. We report low-temperature magnetoresistance (MR) and Hall effect measurements of untwinned epitaxial films of CaRuO₃. The extraordinary Hall effect measurements reveal uniaxial magnetocrystalline anisotropy reflected in anisotropic paramagnetic susceptibility. The MR is positive and data with the magnetic field applied at different angles can be scaled assuming the dependence of the MR on the magnitude of the magnetization. We use this scaling to determine that at 2 K the ratio between the susceptibilities along the easy and hard axes is ∼ 2.9. These results enable the separation between the contribution of the ordinary and the extraordinary Hall effect and the determination that at 2 K the charge carriers are holes and their density is ∼ 2.4 × 10²² cm^{- 3}.