Antiferromagnetic coupling in (111)-oriented Co/Pt superlattices

Nuclear magnetic resonance (NMR) and low-temperature magnetization measurements are used to demonstrate antiferromagnetic (AF) coupling in molecular beam epitaxy grown (111)-oriented Co/Pt superlattices. Drastic changes in the NMR spin-echo spectra as a function of the in-plane dc magnetic-field strength provide conclusive evidence of AF interlayer coupling in these structures, consisting of 35- and 52- Co and 18- Pt bilayers. The structure of the Co films is mainly hcp (70%) and the coupling energy per unit area, as determined from in-plane magnetization loops is found to range up to 1 erg/cm2. © 1994 The American Physical Society.