Structural and magnetic studies of an artificial Eu/Mn superlattice

Artificial superlattice materials composed of alternating layers of europium and manganese metals with a periodicity in the range of 19–227 Å were prepared by means of molecular-beam epitaxy. In situ reflection high-energy electron diffraction observations revealed that the Eu metal layer is amorphous up to a thickness of 23 Å, while a [110]-oriented single-crystal Eu layer grows over the amorphous Eu layer as the thickness exceeds 23 Å. On the other hand, the manganese layers were found to always be in an amorphous state independent of the thickness. The synthesized Eu/Mn systems exhibited a unique magnetic property associated with a magnetic interaction between the amorphous Eu layers.