Molecular dynamics simulation of thin film growth on giant magnetoresistance corrugated structures

Abstract

This paper presents the use of molecular dynamics (MD) in simulating thin-film growth on giant magnetoresistance corrugated structures. The simulation model mainly concerns the deposition of Co atoms on a $V$-shape Cu substrate. The many-body, tight-binding potential model is utilized in the MD simulation to represent the interatomic force that exists between the atoms. The interface width is used to quantify the variation of surface roughness at the transient and steady states. The paper investigates the influence of incident energy on the deposited film surface property and on the growing mechanism, for both vertical and oblique deposition. The results demonstrate how the growing characteristics are influenced by different incident energies and by different deposition directions. It is found that at relatively low incident energies the film growth tends to be in a three-dimensional cluster mode and that a void track is formed, whose growing direction is almost equal to the surface normal to the two inclined surfaces. The uneven thickness found along the base of the $V$ shape is mainly due to the deposited atoms that accumulate at the bottom of the $V$ groove when the incident energy is at a relatively high level. It is found that there exists an optimal incident energy that produces the best film surface property. The film surface property can be improved by changing the incident direction relative to the two inclined directions of \ifmmode\pm\else\textpm\fi{}45\ifmmode^\circ\else\textdegree\fi{}. Smaller deviation angles yield better film surface properties for low incident energy. Conversely, higher levels of incident energy result in worse film surface properties.