TEMPERATURE-DEPENDENCE OF THE 90-DEGREES COUPLING IN FE/AL/FE(001) MAGNETIC TRILAYERS

The temperature dependence of the unusual magnetic 90-degrees coupling in epitaxial Fe/Al/Fe(001) trilayers has been determined. For specific values of applied field and temperature, in-plane anisotropy and the interlayer coupling drive abrupt first-order changes in the temperature-dependent moment of these trilayers. The occurrence of such a first-order transition can be used to determine the value of the interlayer coupling constant, J(Q), at the transition temperature. We show that Fe/Al/Fe(001) trilayers also exhibit distinct second-order transitions in the temperature-dependent moment, and that the occurrence of a second-order transition can similarly be used to specify J(Q)(T). A comparison is made of the values of J(Q)(T) determined by these two approaches, and the dependence of J(Q) on T is analyzed.