Interlayer thickness dependence of 90° exchange coupling in Co_2MnAl/Cr/Co_2MnAl epitaxial trilayer structures

摘要

The spacer layer thickness dependence of interlayer exchange coupling has been investigated in the fully epitaxial trilayers of the Co_2MnAl (CMA)/Cr/CMA structure. A series of high-quality samples of CMA (20 nm)/Cr (t_(Cr) = 0.3 - 8.1 nm)/CMA (10 nm) trilayers was prepared on a MgO substrate by ultrahigh vacuum compatible dc sputtering. Comparison of the results of the experiments and the simulations of magnetization curves revealed novel behavior, dominating the 90° coupling and the absence of 180° coupling. No clear oscillation, only a peak of the 90° coupling strength (J_2 ～ -0.68 erg/ cm~2), was observed at t_(Cr)=1.2 nm.