In situ observation of the strain of Co and Ni deposited on Pd (111) by reflection high energy electron diffraction

Abstract

Co/Pd(111) and Ni/Pd(111) bilayer films were grown epitaxially on single crystal MgO (111) substrates by ultrahigh vacuum deposition. In situ observation of the strain of Co and Ni deposited on Pd (111) plane was performed by reflection high energy electron diffraction (RHEED) during fabrication. From RHEED patterns it was confirmed that the lattice constant of a Co film of 2 Å in thickness deposited on Pd was about 3.7 Å, which was different from that of Pd (3.89 Å). The strain (εCo) of the Co layer was rapidly released during further Co deposition. The strain εCo of the third Co monatomic layer on Pd is nearly equal to zero. The large strain of the Co layer is localized at about one or two monatomic layers of the interface between Co and Pd. On the other hand, a Ni film deposited on Pd was not strained from the beginning of the deposition. The relationship between the perpendicular magnetic anisotropy of Co/Pd and Ni/Pd compositionally modulated multilayer films and the strain of Co and Ni is discussed.

Modulation of magnetic coercivity in Ni thin films by reversible control of strain

“…Actually previous works have reported that Pd thin film preferred (111)-orientation when grown on mica [40,41]. The matching between Ni(111) and Pd(111) has also been suggested in Pd/Ni(111) and Ni/ Pd(111) systems [42,43]. Combining the information from previous studies, the (111)-texture of Pd/Ni/Pd/mica observed in our measurement is reasonable.…”

Perpendicular Magnetic Anisotropy of Co/Pd(111) Studied by Spin-Resolved Photoelectron Spectroscopy

“…The lattice strains of the Co films have been observed by means of EXAFS, XPD, Xray diffraction and RHEED experiments. [11][12][13][14][15] However, it was noticed that the PMA of Co/Pd(111) cannot be explained only from the viewpoint of the magnetoelastic anisotropy. 15) On the other hand, it is considered that the anisotropy of the orbital moment and the spin-orbit interaction in the electronic structure cause the PMA.…”

The structure at the interface of Ni/Pd bilayer films with different deposition sequences estimated from molecular dynamics simulation

“…Table I shows the average strain ( E ) in 1st deposited layer of Pd on Ni or Ni on Pd derived from the simulated results. Yamazaki et al [7] reported that they observed the strain in Ni layer on Pd (111) by using RHEED during evapolation and there was no strain at interface. This corresponds well to the simulated result.…”