In situ magnetoelastic coupling and stress-evolution studies of epitaxial Co35Pd65 alloy films in the monolayer regime

Abstract

We report in situ measurements of magnetoelastic coupling, B 2 , and stress, , in Co 35 Pd 65 alloy films epitaxially grown on a Cu/Si͑001͒ substrate in a thickness range of 1-10 ML by means of a highly sensitive optical deflection-detecting system. It was found that the value of B 2 increases from 0.72ϫ10 7 J/m 3 at 2 ML to 3.31ϫ10 7 J/m 3 at 10 ML. A second-order strain correction of B 2 ϭB b ϩC 1 ⑀ϩC 2 ⑀ 2 rather than a first-order one of B 2 ϭB b ϩC 1 ⑀ provides a better fit for the observed behavior of B 2 versus film strain, ⑀, where B b is the bulk value. The relationship between B 2 and ⑀ observed in the present study reveals that the second-order correction is crucial for understanding the dependence of B 2 on ⑀ in an ultrathin regime.

In situ layer-resolved magnetoelastic coupling and growth stress study of Co/Pd nanomultilayer films

“…Recent studies on magnetoelastic coupling (MEC) of ultrathin films show that the MEC of ultrathin films could be drastically changed at the film interface compared to the bulk one. Thus, in addition to the bulk MEC, interface alloy formation or the existence of strain due to the lattice mismatch at the interface is generally introduced to explain the behavior of MEC near the film interface or surface [1,2]. However, it is still unclear as to which mechanism plays a key role in the MEC of ultrathin ferromagnetic films.…”

“…1(a) shows an enlarged plot for the stress evolution in the sixth Pd sublayer. Note that the stress evolutions in Pd sublayers show typical coherentto-incoherent transition caused from lattice mismatch between Pd and Co [2].…”

“…The MEC and growth stress of the film were measured by a highly sensitive laser-deflection system, using a one-dimensional position-sensitive detector (PSD). Stress and MEC were determined from the change of curvature (R) of the substrate, using Stoney's formula [2].…”

Magnetoelastic properties of Co/Pd nanomultilayer films

“…One of the important issues in the area of ultrathin ferromagnetic films is their magnetoelastic property, since the magnetoelastic property could provide a new way to control the spin orientation and to enhance new magnetic anisotropy in magnetic devices [4][5][6]. Recent studies on magnetoelastic coupling (MEC) of ultrathin films show that MEC of ultrathin films can be drastically changed at the film interface compared to the bulk.…”

Early Stage Growth Structure and Stress Relaxation of CoCrPt Thin Films on Spherically Modulated Polymer Surface

“…1. Details of the measurement system are reported elsewhere [15,16]. The level of growth stress was determined from the change in curvature (R) of the substrate using the following equations [17]: (1) where Y s , ν s , and t s are Young's modulus, Poisson's ratio, and substrate thickness, respectively, and t f is the film thickness.…”