Studies on the anisotropic properties of MgB2

This paper presents a review on reported anisotropic properties of MgB2. The first direct measurement of an anisotropic superconducting property in MgB2was achieved for the bulk nucleation field Hc2, in samples of aligned crystallites. A ratio / ~ 1:7 was found between the critical field parallel to the ab plane and parallel to the c axis direction. Further, detailed study of the Hc2 angular dependence confirmed its bulk origin, in contrast with what would be expected for the surface nucleation fi...