We present data on temperature-dependent anisotropy of the upper critical field of MgB2 obtained from the analysis of measurements on high-purity, low-resistivity polycrystals. The anisotropy decreases in a monotonic fashion with increase of temperature.
American Physical Society
Sergey L. Bud'ko and Paul C. Canfield. "Temperature-dependent Hc2 anisotropy in MgB2 as inferred from measurements on polycrystals" Physical Review B
Vol. 65 Iss. 21 (2002) p. 212501
Available at: http://works.bepress.com/paul_canfield/11/