GROWTH OF FE(110)/BCC NI(110) SUPERLATTICES BY MOLECULAR-BEAM EPITAXY

We have grown a series of Fe(110)/bcc Ni(110) superlattices by MBE. RHEED and X-ray analysis indicated that even for Fe thicknesses of only 2 ML, the subsequent Ni layer could be grown in a pseudomorphic phase with a structure resembling that of the Fe template up to a thickness of 8 ML. Magnetometry determined that this distorted bcc phase is ferromagnetic at room temperature. Transmission Mossbauer spectroscopy implied the existence of two magnetic Fe sites, one we associate with Fe atoms that have diffused into the Ni layers and the other with Fe atoms that mainly coordinate other Fe atoms. The diffused site showed no magnetic splitting at 300 K in an Fe(110)/Ag(111) film that was grown for comparison to the Fe(110)/Ni films, implying that the distorted bcc Ni(110) is magnetic.