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SUMMARY:Materials from Mathematics - Richard James (University of Minnesot
 a)
DTSTART:20190115T090000Z
DTEND:20190115T094500Z
UID:TALK116878@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:We present some recent examples of new materials whose synthes
 is was guided by some essentially mathematical ideas.  They are materials 
 that undergo phase transformations from one crystal structure to another\,
  with a change of shape but without diffusion.  They are hard materials\, 
 but nevertheless show liquid-like changes of microstructure under a fracti
 on of a degree change of temperature.  The underlying mathematical theory 
 was designed to identify alloys that show low hysteresis and exceptional r
 eversibility.   The new alloys\, of which Zn_45Au_30Cu_25 and Ti_54.7Ni_30
 .7Cu_12.3Co_2.3 are currently the best examples\, do show unprecedented le
 vels of these properties\, but also raise fundamental questions for mathem
 atical theory. Magnetoelectric properties of solids are often sensitive to
  lattice parameters\, so they can be switched on and off at a phase transf
 ormation: briefly\, multiferroism by reversible phase transformation.  Thi
 s switching can be combined with induction in the ferromagnetic case\, or 
 capacitance in the ferroelectric case\, to yield devices that convert heat
  directly to electricity\, without a separate electrical generator. We des
 cribe briefly the associated mathematical theory.  The resulting multiferr
 oics provide interesting possible ways to recover the vast amounts of ener
 gy stored on earth at small temperature difference.  They move heat produc
 ed by natural and man-made sources from higher to lower temperature and th
 erefore contribute negatively to global warming.
LOCATION:Seminar Room 1\, Newton Institute
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