Magnetization of (100) Cu-Ni, (100) Cu-Co, and (100) Ni-Co superlattices deposited on silicon using a Cu seed layer

The magnetization of (100)Cu-Ni, (100)Cu-Co, and (100)Ni-Co superlattices has been studied. The structures were grown on the (100)Cu/Si substrates, with the (100)Cu epitaxially grown on the (100)Si as the seed. The (100)oriented superlattices show different magnetization curves from the (111) structures and from bulk (100)Ni and Co films. A much enhanced magnetization is observed for the (100)Cu-Ni superlattice with the field perpendicular to the film plane. The remanence is larger than that for the field parallel to the film plane. Negative remanence and coercivity are observed for the (100)Cu-Co and Ni-Co structures. The magnetization curve for the (100)Ni-Co superlattice is further shown to resemble a superposition of the Cu-Ni and Cu-Co ones. Upon heating the Ni-Co structure to 400°C to consume more Ni than Co, a magnetization curve similar to that of the Cu-Co one is observed.