Molecular-beam-epitaxial growth and magnetic properties of (111)Pt/Co/Ag, Pt/Co, and Ag/Co/Pt superlattices

Abstract

The structural and the magnetic properties of (111)Pt/Co/Ag, Pt/Co, and Ag/Co/Pt superlattices (SLs) were studied. The samples were grown at 373 K on Ag buffer layers preformed on 7×7-(111)Si substrates by molecular-beam epitaxy. Reflection high-energy electron diffraction indicated that in-plane lattice constants of Co, Pt, and Ag layers changed continuously during layer growth in Pt/Co/Ag SLs with thin Co layers and Pt/Co SLs. The effective magnetic anisotropy energy Keff of a Pt/Co/Ag SL was similar to K̄eff, an average of Keff values of a Pt/Co and an Ag/Co SL with the same Co layer thicknesses. This suggests that the origins of perpendicular magnetic anisotropy in the Pt/Co system are different from those in the Au/Co system investigated earlier, in which the difference between the Au/Co and Au/Co/Ag SLs is small in Keff value.

Growth of composition-modulated Ag/Co wires on Pt(997)

“…As a consequence, they have been the object of numerous studies that looked at the connection between structure and transport properties. 9,12,13 Quite naturally, most of the attention to date has been directed towards two-dimensional ͑2D͒ layered films, since many devices used for microelectronics or magnetorecording applications are based on multilayer structures. However, technological progress will likely require devising and characterizing more complex structures in less than two dimensions.…”

Stiffened Ultrathin Pt Films Confirmed by Acoustic-Phonon Resonances

“…Motivated by the discovery of the elastic anomaly, many researchers followed, but most reported negative results for the supermodulus effect [2]. As shown through the perpendicular magnetic anisotropy, a large in-plane strain (10 ÿ2 ), should occur at the interfaces in some superlattice systems (Co=Pt, for example [3] ), but the sign of the strain turns out to be opposite across the interfaces. The periodic compression or tension strains in multilayers cancel the changes of the elastic constants in individual layers, making it difficult to observe the elastic anomaly.…”

Increasing Magnetic Anisotropy in Bimetallic Nanoislands Grown on fcc(111) Metal Surfaces

“…Rh and Pd are considered as highly polarizable [ 17 , 18 ]; therefore, their hybridization at the interface or interline with the Co core should result in large, induced magnetic moment and contribute to the MAE of the nanoisland [ 7 ]. On the other hand, Ag usually shows very small polarization at the interface with a ferromagnetic element [ 19 , 20 , 21 , 22 ]. Hence, it is interesting to investigate whether an Ag interline (or interface) contributes to the MAE, or whether it simply acts as a passivating and protecting shell for the Co-core.…”