  The intrinsic pinning properties of FeSe0.5Te0.5, which is the superconductor
with Tc of about 14 K, were studied by the analysis of magnetization curves by
the extended critical state model. In the magnetization measurements by SQUID
magnetometer, the external magnetic fields were applied parallel and
perpendicular to c-axis of the sample. The critical current density Jc's under
the perpendicular field of 1 T were estimated by using the Kimishima model as
about 1.6 x 10^4, 8.8 x 10^3, 4.1 x 10^3, and 1.5 x 10^3 A/cm2 at 5, 7, 9, and
11 K, respectively, and the temperature dependence of Jc could be fitted with
the exponential law of Jc(0)xexp(-{\alpha}T /Tc) up to 9 K and power law of
Jc(0)x(1-T / Tc)n near Tc.
