  Specific heat measurements were used to study the magnetic phase transition
in Ga1-xMnxAs. Two different types of Ga1-xMnxAs samples have been
investigated. The sample with a Mn concentration of 1.6% shows insulating
behavior, and the sample with a Mn concentration of 2.6% is metallic. The
temperature dependence of the specific heat for both samples reveals a
pronounced lambda-shaped peak near the Curie temperature, which indicates a
second-order phase transition in these samples. The critical behavior of the
specific heat for Ga1-xMnxAs samples is consistent with the mean-field behavior
with Gaussian fluctuations of the magnetization in the close vicinity of TC.
