Temperature-driven in-plane anisotropy reorientation transition in Fe(110) films

The competition between surface and volume magnetic anisotropy in ultra-thin films may induce a dramatic thickness and temperature dependence of the anisotropy. Whereas the former has been studied extensively, only a few reports have appeared on the latter for in-plane anisotropy. We have analysed such an in-plane reorientation in a W(110)/Fe(110)(60 A)/W(110) film, which occurs because of the differences in the temperature dependencies of the various contributions involved in the total anisotropy. The second-order interface anisotropy constant is deduced for this system (100 to 300 K) from total anisatropy measurements and subtraction of bulk contributions. The thermal variation of the interface anisotropy constant with the reduced spontaneous magnetization m(s) is found to follow an m(s)(13/2) law. Phase diagrams are derived.