In this work, the investigators propose a new "magnetic field induced configurational force" on ferromagnetic surfaces and ways to exploit it to accomplish "guided assembly" of patterns of any desired order and size distribution at nano to micro scale. They present results of their preliminary experiments to demonstrate the feasibility of their idea of "magnetic field induced surface diffusion" and request funding to explore this new phenomenon further to achieve better control over the process, gain a fundamental understanding and also develop it into a novel nano-manufacturing technique for ferromagnetic surfaces. In addition to the experimental investigation, the proposed research includes development of an analytical framework to describe the kinetics and a quantitative description of the phenomenon.
Fabrication of controlled and ordered patterns of nanostructures of technological interest has been the focus of several research efforts during the past decade. An example of such efforts is the strain induced self-assembly in semiconductor thin films that exploits an elastic configurational force that arises as a consequence of the competition between elastic energy and surface energy in minimizing the system free energy. A relevant question in this context of nanoscale assembly and fabrication is whether there are other kinds of configurational forces at nanoscale that act on solid surfaces, which can be exploited to drive ordered and controlled structure growth. In case of ferromagnetic surfaces, this proposal (i) demonstrates the existence of a magnetic configurational force and presents supporting preliminary experimental evidence and (ii) seeks to explore it further in a systematic experimental program. This configurational/driving force results from the competition between magnetic field energy and surface energy. Under favorable conditions, the magnetic configurational force can induce surface shape evolution through surface diffusion.
The intellectual merit of this proposal lies in exploring a new concept of driving surface diffusion in ferromagnetic materials using magnetic field. This concept has not been discussed or reported before. Based on this new idea, the proposal also aims to develop a new nanofabrication tool to accomplish "guided assembly" of patterns of nanostructures with any desired spatial location and size distribution. The proposed research also aims to develop an analytical description of the phenomenon by introducing the concept of magneto-elastic chemical potential. The research will be based on a synergistic interdisciplinary collaboration between the principal investigator and his collaborator, with respective backgrounds in Applied Mechanics and Materials Science.
The broader impact of the proposed research lies in (i) wide and effective dissemination of the insights gained through this research, (ii) training a graduate student as part of his/her Ph.D. program, (iii) providing research and educational opportunities to undergraduate students from a Historically Black College or University (HBCU) and (iv) interacting with Brown's NSF supported MRSEC program to include this research project in the Research Experience for Teachers (RET) outreach program. The graduate and undergraduate students working on this project will be provided opportunities to participate in research conferences to present their work and gain valuable career experience.
