Magnetic Nanosystems Group
Welcome to the Yellen Research Group!
The Yellen group is currently looking for postdocs, graduate and undergraduate students to undertake experimental and computational studies.
POSTDOCTORAL ASSISTANT OPENING: Professors Benjamin Yellen and Stefan Zauscher are looking for a postdoctoral assistant to study the effect of ferroelectric thin films on surface chemical reactions. For more information about the position, please contact yellen@duke.edu
GRADUATE STUDENT OPENING: Professors Benjamin Yellen and Lawrie Virgin are looking for a graduate student to study the motion of colloidal particles exposed to a traveling magnetic field wave. This work will consist of a combination of experimental and computational studies. For more information about the position, please contact yellen@duke.edu
UNDERGRADUATE STUDENT OPENINGS: There are various projects available for undergraduate students. For more information, contact yellen@duke.edu
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Prof. Yellen's research group investigates programmable techniques for manipulating colloidal particles with potential applications in electronic, photonic, and biomedical devices. The main focus of his group is the investigation of complex interactions between micrometer and nanometer sized colloidal particles and magnetic recording media commonly used in the data storage industry. His current reseach interests can be sub-divided into three main areas:
Concentration gradients in mixed colloidal particle suspensions. Theoretical and experimental techniques are used to study the formation of concentration gradients in mixed suspensions of magnetic and nonmagnetic particles.
Controlling the alignment of nanorods. Theoretical and experimental investigations are used to study the controllability of nanorod alignment in inhmogeneous magnetic field.
Transport of colloidal particles in traveling periodic potential energy landscapes. The movement of magnetic micro-beads in a traveling magnetic field wave generated near the surface of a micro-fluidic device is investigated for applications in biological separation.
Scientific Background: In the last few decades, great advances have been made in the fabrication and characterization of nanomaterials, such as carbon nanotubes, semiconducting nanorods, quantum dots, and other exotic materials displaying unique properties suitable for a myriad of electronic, photonic, and biomedical device applications. Far less attention, however, has been paid to the large scale integration of these exotic materials into useful engineering systems. Since most of these designer materials are not amenable to monolithic integration, there has been recent interest in devising techniques for arranging these materials into high level system architectures by alternative methods. One such technique, known as “directed self-assembly”, has been proposed as a cost-effective method for building integrated systems from nanoscale building blocks. Compared with the field of robotics, “directed self assembly” has the advantage (and disadvantage) of operating on millions of colloidal components in a parallel fashion. The advantage to a parallel approach for manipulating colloidal components compared with the serial robotic approach is clearly one of efficiency. The disadvantage of directed self-assembly, however, is the higher likelihood for errors in the assembled devices. It is precisely this perceived disadvantage which has inspired me to focus my research in this area and to explore the controllability of self-assembly processes. In particular, I am interested in learning what physical parameters can be exploited to build useful engineering devices while minimize the error rates in self-assembling systems.
For more information, see the research page.
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