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SUMMARY:Evidence for Unusual Magnetic Order in Cubic FeGe beyond its Quant
 um Phase Transition - Heribert Wilhelm\, University of Geneva\, Switzerlan
 d and Diamond Light Source
DTSTART:20091125T111500Z
DTEND:20091125T121500Z
UID:TALK19544@talks.cam.ac.uk
CONTACT:Michael Sutherland
DESCRIPTION:Transport measurements on the cubic modification of FeGe under
  high pressure have shown that the long-wavelength helical order (T_C=280K
 \, at p=0) is suppressed at a critical pressure p_c~19GPa [1]. The metalli
 c ground state persisting above p_c can be described by band-structure cal
 culations if zero-point motion is included. However\, the electrical resis
 tivity shows that the ground state can not be described by\nFermi-liquid t
 heory in a wide pressure range above p_c. This non-Fermi liquid behavior s
 uggests that the phase transition occurs without quantum criticality. New 
 information based on nuclear forward scattering measurements (p<30 GPa\, T
 >3 K) revealed a finite but disordered magnetic moment above p_c and low t
 emperature. The implication of this finding to the metallic ground state a
 nd an updated phase diagram will be discussed.\n\n[1] P. Pedrazzini et al.
 \, Phys. Rev. Lett. 98\, 047204 (2007).
LOCATION:Mott Seminar Room\, Cavendish Laboratory\, Department of Physics
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