An understanding of the growth and behavior of thin films is quite important for both basic research as well as applied industrial uses. There is hardly a technological field today that does not make some use of thin films (usually with a very complicated architecture.) In our lab my students and I design and build thin film structures in order to study a wide range of interesting problems. Two examples of the range of problems under study are:

Two-dimensional magnetism: When a material is made thin enough, it behaves as if it were, in fact, two-dimensional. We have recently developed and demonstrated a method of making materials that are two-dimensional as far as the magnetic behavior is concerned, but that retain all of the other three dimensional normal properties. Before our work, everyone who changed the dimensionality of a material also made other changes making a theory of such materials impossible. We are currently exploiting this discovery by studying different magnetic states in two-dimensions.

The Temperature of the Earth's Core: The earth has an inner solid core made up mostly of iron and a liquid outer core made up of an iron alloy. Knowing the temperature of the boundary between the inner and outer cores is necessary for an understanding of the earth. We cannot directly measure this temperature but we know it must be near where iron melts when it is subjected to 4 million atmospheres. Estimates of this melting point have ranged from 4000 K to 8000 K. In collaboration with Lawrence Livermore National Laboratory we have recently directly measured this temperature by driving a shock wave through a thin film and measuring the radiation produced by the hot film. From these measurements, we found a melting temperature of 6800 K (plus/minus) 500 K.

Honors and Awards
for
David J. Webb

Memberships
  • American Physical Society

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    E-mail webb@physics.ucdavis.edu

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