2006 Bertram E. Warren Diffraction Physics Award

Chuck Majkrzak

The following is an article in the Newsletter of the American Crystallographic Association. Dr. Majkrzak received his award at the 2006 ACA Annual Meeting in Honolulu.

ACA is pleased to announce that the recipient of the 2006 Warren Award is Dr. Charles F. Majkrzak of the National Institute of Standards and Technology (NIST). Dr. Majkrzak is cited for his seminal contributions to the development of neutron reflectivity and for his pioneering work in the exploration of many issues in interface science using this technique.

Dr. Majkrzak earned his Bachelor's degree in Physics in 1972 from Montclair State College and his Ph.D. in Physics from the University of Rhode Island in 1978. He did his postdoctoral research at Brookhaven National Laboratory and was a visiting scientist in IFF/KFA, Juelich, Germany during the summer of 1983, before becoming a permanent member of Brookhaven's Physics Department in 1984. Dr. Majkrzak left Brookhaven for a position at the National Institute of Standards and Technology in 1987, where he is now the Leader of the Surfaces and Interfacial Science team at the NIST Center for Neutron Research.

Dr. Majkrzak's unusual technical and scientific creativity have profoundly advanced neutron reflectometry, the theory for polarized neutron reflectometry, and have led to the development of important new methods of data analysis. While his contributions to this technique are widely recognized, of particular note is how Dr. Majkrzak designed, optimized, and made creative use of supermirror polarizers, integrating them into neutron instruments that attain very low backgrounds and consequently the highest signal-to-noise achieved anywhere. This point is crucial to achieving the widest possible wave vector range of data, and thereby providing the highest spatial resolution and thus the most detailed and reliable structural information available.

In the tradition of Prof. Bertram E. Warren, Dr. Majkrzak applied his ideas and methods to a wide range of scientific problems of both fundamental and technological importance. He led a seminal study of Gd/Y rare-earth multilayers that revealed an oscillatory exchange coupling spanning non-magnetic layers. This research provided the basis for interpreting similar effects in transition metal multilayers that exhibit giant magnetoresistance (GMR), which is now the heart of present-day magnetic read heads in hard disk drives. Dr. Majkrzak's scientific foresight enabled him to recognize that neutron reflectometry would be an extremely powerful method with which to study biological and soft matter systems. He performed a classic series of neutron reflectometry experiments on the surface-induced ordering of block copolymers, and has more recently explored the structure of biological and biomimetic membranes. The structure of self-assembled biological membranes, particularly with proteins and other molecules inserted into the lipid bilayers, poses a significant new challenge because, unlike previous systems where the basic structure is controlled and known, the basic structure of the self-assembled system is not known a priori. Refinements of the structure of these new systems using the dynamical theory of diffraction can lead to significantly erroneous results because of the phase ambiguity.

To address this problem, Dr. Majkrzak and his collaborators developed an exact, first-principles method to analyze specular reflectivity data. The culmination of their efforts was a solution to the phase problem for neutron reflectivity that allowed the direct inversion of the reflection amplitude, using the Gel'fand-Levitan-Marchenko integral solution, to obtain the scattering length density profile uniquely within the dynamical theory of diffraction. This method involves the use of a layer, a substrate, or fronting material that can be used as a reference, and is of immense importance for neutron reflectivity studies of unknown structures. Dr. Majkrzak's extraordinary contributions to the field of neutron reflectometry and diffraction physics are the result of a rare blend of scientific, engineering, and technical talents that richly qualify him to continue the outstanding traditions of the Warren Award.

Last modified 11-August-2006 by website owner: NCNR (attn: )