Anisotropic superconducting properties of aligned MgB(2) crystallites.

Samples of aligned MgB(2) crystallites have been prepared, allowing for the first time the direct identification of an upper critical field anisotropy H(ab)(c2)/H(c)(c2) = xi(ab)/xi(c) approximately 1.7, with xi(o,ab) approximately 70 A, xi(o,c) approximately 40 A, and a mass anisotropy ratio m(ab)/m(c) approximately 0.3. A ferromagnetic background signal was identified, possibly related to the raw materials purity.