A New Method for the Estimation of Hc2 Anisotropy in Polycrystalline MgB2 Samples

By using isothermal magnetization measurements in polycrystalline MgB2 samples, we estimate the Hcc2 in the interval [0, Tc]. By combining these measurements to the estimated Habc2 from the onset of the diamagnetic transition in isofield and isothermal magnetic measurements, an estimation of the anisotropy parameter can be achieved. The Hcc2 values coming from high quality polycrystalline samples agrees nicely to those obtained on single crystals. Our results show a temperature variation of the γ(T ) = Habc2/Hc2 with γ(Tc) ≈ 3.