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, sigma, in Co35Pd65 alloy films epitaxially grown on a Cu/Si(001) 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 0.72x10(7) J/m(3) at 2 ML to 3.31x10(7) J/m(3) at 10 ML. A second-order strain correction of B-2=B-b+C(1)epsilon +C(2)epsilon (2) rather than a first-order one of B-2=B-b+C(1)epsilon provides a better fit for the observed behavior of B-2 versus film strain, epsilon, where B-b is the bulk value. The relationship between B-2 and epsilon observed in the present study reveals that the second-order correction is crucial for understanding the dependence of B-2 on epsilon in an ultrathin regime. (C) 2001 American Institute of Physics.