  It is found in the Pt/Co/Pt(111) sandwiches that perpendicular magnetic
anisotropy weakens associated with the dramatic magnetization enhancement as
the temperature decreases below a critical temperature, T_cri, which increases
with the Pt overlayer thickness t_Pt. For the sandwich with enough thick Pt
overlayer, it trends to an unusual state with weak perpendicular magnetic
anisotropy in the absence of obvious easy direction behavior at low
temperature. It suggests that Pt is more significantly polarized in the film
with thicker Pt overlayer. The results reveal the strong influence of both
thick nonmagnetic coverage and temperature on the electronic structure of the
Pt/Co/Pt(111) sandwich.
