Nuclear Orientation as a Tool for Investigation of Magnetic Multilayers with Rare Earths

Abstract

Low-temperature nuclear orientation (NO) is presented as a useful tool to study the behaviour of rare earth (RE) ionic magnetic moments in magnetic multilayers. NO is shown to give rather direct information about the direction of RE ionic moments in such low-dimensional systems. In particular, the perpendicular magnetic anisotropy (PMA) can be directly monitored using RE atoms as probes. The potential of NO is demonstrated by our recent results, which concern the Fe/Tb multilayers. We have studied NO of ¹⁶⁰Tb in Fe(40 Å)/Tb(x Å) (x = 5–30) and found that the Tb magnetic moments show PMA at low external magnetic fields (B_ext). PMA of the Tb spins is found to be more pronounced when the Tb layer is thinner. It was found that B_ext has a complicated influence on the Tb magnetic moment misalignment, which is connected with an interplay between PMA, the exchange interactions and the shape and magnetic crystalline anisotropy.