Misfit Dislocation Nucleation Kinetics Studied by Magnetic Properties in Epitaxial Ni/Cu Films

在超过临界厚度的外延薄膜中，失配位错在热力学上是稳定的，这主要取决于薄膜和衬底之间的失配程度。当超过临界厚度时，位错的形成不会立即发生，因为涉及到没有充分了解的动力学因素。这项资助研究了失配位错和应变在影响磁性薄膜行为中的作用。研究了外延薄膜中位错成核的动力学，旨在发展一种原位监测失配位错形成的方法。磁光克尔(MOKE)效应被用作对磁性薄膜中存在的小应变敏感的探针。这被用来表征外延镍/铜薄膜上的失配应变和位错。其他使用的技术是电子显微镜和二次电子自旋极化分析，以确定位错形成的动力学。晶格失配的均匀应变和位错周围高度不均匀的应变对磁性有很大的影响。这项研究的目的是为了更好地理解失配位错的形成及其对磁性薄膜的影响。这项研究可能会产生一种薄膜生长过程中的现场监测技术。

Misfit dislocations are thermodynamically stable in epitaxial films above a critical thickness, which depends mainly on the misfit magnitude between the film and substrate. The formation of dislocations does not occur immediately when the critical thickness is exceeded since kinetic factors are involved which are not adequately understood. This grant examines the role of misfit dislocations and strain in affecting behavior of magnetic films. The kinetics of dislocation nucleation in epitaxial thin films is pursued with an aim towards developing an in-situ method for monitoring misfit dislocation formation. The Magneto-optic Kerr (MOKE) effect is employed as a probe that is sensitive to the presence of small strains in magnetic films. This is used to characterize misfit strains and dislocations on epitaxial nickel/copper films. Other techniques employed are electron microscopy and secondary electron spin polarization analysis to determine the kinetics of dislocation formation. %%% The homogeneous strain of lattice mismatch and the highly non- uniform strains around dislocations have dramatic effects on magnetic properties. This research is directed towards developing a better understanding of the formation of misfit dislocations and their effects on magnetic films. An in-situ monitoring technique during film growth could result from the research.