Dr. Hailemariam Ambaye
Currently, I am a staff scientist at the Spallation Neutron Source of the Oak Ridge National lab operating the magnetism reflectometer instrument with my colleagues. I joined ORNL-SNS in 2006 as post doctorial scientist. The magnetism reflectometer instrument is one of the three instruments that came online in 2006 when the SNS, the world's brightest source became operational. A reflectometer in general is useful to study wide range of science, including magnetic thin films, superlattices, surfaces, interfacial studies in polymers, cell-membrane analogues, biomimetic films, and surface chemistry involving thin layers of surfactants or other materials deposited on liquid surfaces.
I graduated with the BS in physics from the physics department (Addis Ababa University) in 1990, I have since been involved in several different research areas. I worked on understanding diffusion processes in disorder systems as part of my graduate degree research. The result of this work was published in 1995 in physical review as my first publication. The first exposure to this field came about when I did my senior project with Dr. Mulugeta, the man that I have tremendous respect, admiration and love for. The project was based on an article that was published around that time by Prof. Klaus Kehr of Juelish, Germany. This project opened up windows of opportunity for me, which I had ultimately ploughed through. Having done this project, I subsequently contacted Prof. Kehr if I could do my graduate research under his supervision in Germany for which I had the financial support from the German Academic Exchange service (DAAD in German). Immediately after I have gotten my master degree in 1995, I applied for DAAD scholarship for my PhD in physics with my German advisor's support while at the same time preparing to take TOEFL and GRE to come to the US for the same purpose. The DAAD scholarship offer came before any of the other applications that I had been sending out. So one year after I finished my master degree I began my PhD research at Juelich research center (formerly nuclear research center), Germany.
The highlights of the research that I have done during my stay in Germany were understanding of molecular motors using hopping models and also the application of statistics of extreme events in transport systems such as diffusion processes and traffic flow. After three papers and less than a year to finish my PhD, I came to Clemson University and started over my PhD. It was not easy making that decision. I teetered and labored a lot to get to it nonetheless made that difficult decision of abandoning my almost finished PhD and came to the USA.
My PhD research at Clemson was basically on developing a theoretical model/ numerical calculations of molecule surface scattering, which includes energy and momentum transfers between the surface and projectile for translational motion, rotational energy exchange and internal mode excitation. We studied scattering of diatomic and poly-atomic molecules from metal surfaces based on the model developed.
Now at the Spallation Neutron Source in ORNL, I am developing a research project on Magnetic tunnel junctions (MTJs), spin valves and possible graphene Magnetic multilayer systems. The electronic transport processes in particular in MTJ based devices, depends on the magnetization state of the two magnetic layers. It is believed that interfaces between the different layers play a crucial role for spin polarized transport in MTJ. Polarized Neutron reflectivity would be the right technique to figure out the different interface configurations of the insulator/ferromagnetic interfaces and also the magnetic state of the system
I taught physics at Alemaya/Haremaya University for two years (90/91-91/92) as an assistant graduate, for one year (95/96) as a lecturer and for about two years (2003-2005) at Greenville College in Greenville, South Carolina before joining the oak ridge national lab, my current institute. I see the applications of physics in many aspects of our life today (in addition to the so many that we know) such as predicting market fluctuations (commercial physics-a Belgian physicist predicted the collapse of Asian market in 1997/98), models to predict political election and also war outcomes (models predicted the outcome of the World War II). Those are some of the Ising model based examples that I came across and read when learning Monte Carlo simulation at the University of Cologne, Germany. Understanding traffic flow in cities and developing models using diffusion processes was a very hot and popular field in the mid 1990s at least in Germany, where I was at that time. Having said all these, physics was not my first choice as a freshman at the science faculty in AAU; I do not think it was even my second. I was pushed to it by the system and I embraced it and tried to get the most that I could out of the life opportunity that was handed to me. The first two years in college were very frustrating to me. I worked very hard and thought I understood the material but the grades were hard to come by. Only in the last two years that I was able to pull my grades up. The down side of not having super grades is that it makes us less competitive when applied for schools in the US since the GPA is one of the first parameters you are measured by, in particular, when you have nothing else to show but your grades. I am hoping things are different now. Despite the challenging process that we had to go through earning our first degree at AAU, I whole heartedly believe that it is the education that was instilled in me back home, especially the one that I have gotten at the physics department that has sustained me so far.
"If you can't explain it simply, you don't understand it well enough".