Transport properties of MgB₂ single crystal

We report the ab-plane and c-axis resistivity of MgB₂ single crystals. The absolute value of the c-axis resistivity is one to two orders of magnitude larger than the in-plane resistivity. The temperature dependencies are almost the same in both directions. Anisotropy in the superconducting state is determined from the resistivity measurements under magnetic field. This is compared to the anisotropy estimated from the normal state resistivity. The fairly good agreement of anisotropy ratio in the normal and superconducting state implies that electronic state of MgB₂ can be analyzed within the three-dimensional effective mass model.