Magnetic structures of an Er/Tb superlattice studied by neutron diffraction

The magnetic structures of an Er (90 Å)/Tb (10 Å) superlattice with the c-axis of the hep structure parallel to the growth direction are investigated by neutron diffraction. As a function of temperature, the magnetic component parallel to the c-axis undergoes the same sequence including the Néel and Curie temperatures as bulk Er, while the component in the basal plane retains a helical ordering at higher temperatures up to 130 K, which is more than twice the corresponding temperature of bulk Er. We argue that the basal-plane ferromagnetic ordering of the adjacent Tb layers has enhanced the development of the basal-plane ordering in the Er layers.