Micromagnetic modeling is used to study the energetics of magnetic switching of single-layer permalloy nanowire. The energy landscape of the system is studied using Nudged Elastic Band method. Using different initial guess trajectories for NEB minimization several alternative minimal energy transition paths were found corresponding to possible scenarios of magnetic switching of the nanowire through nucleation and propagation of transverse domain walls. Dependence of energy barrier for DW nucleation on lateral sizes of the nanowire has been studied. Besides that, the effect of additional constant external bias magnetic fields (longitudinal and transverse) on nanowire switching has been explored. It has been shown that presence of rectangular shape notch on the nanowire long side leads to the appearance of local minimum on the energy profile. Thus artificially created notches can be used for DW pinning.
The results of study of multilayer thin film structure using Rutherford Backscattering Spectroscopy (RBS) are presented. The structure 5(nm)Ta/30CuN/5Ta/3NiFe/16IrMn/2.0CoFe/0.9Ru/2.5CoFeB/2MgO/2.5CoFeB/10Ta/7Ru on SiO2 was used as a test sample. This kind of structure is using for MRAM fabrication. The RBS analysis of such samples might appear significant difficulties during measurement and interpretation of RBS spectra because of small layers thickness and overlay of peaks of elements with close masses. It was found that using different experimental conditions for RBS analysis one can obtain information about the density and thickness of each layer. The data about these parameters are presented.
We present here a summary of some recent techniques used for atomistic studies of thin film growth and morphological evolution. Specific attention is given to a new kinetic Monte Carlo technique in which the usage of unique labeling schemes of the environment of the diffusing entity allows the development of a closed data base of 49 single atom diffusion processes for periphery motion. The activation energy barriers and diffusion paths are calculated using reliable manybody interatomic potentials. The application of the technique to the diffusion of 2-dimensional Cu clusters on Cu(111) shows interesting trends in the diffusion rate and in the frequencies of the microscopic mechanisms which are responsible for the motion of the clusters, as a function of cluster size and temperature. The results are compared with those obtained from yet another novel kinetic Monte Carlo technique in which an open data base of the energetics and diffusion paths of microscopic processes is continuously updated as needed. Comparisons are made with experimental data where available.
Conference Committee Involvement (1)
The International Conference on Micro- and Nano-Electronics 2018