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SUMMARY:Phase transitions in the spin and charge coupled EuTiO3 - Leszek S
 palek (Cavendish Laboratory)
DTSTART:20101122T160000Z
DTEND:20101122T170000Z
UID:TALK26565@talks.cam.ac.uk
CONTACT:Ian Farnan
DESCRIPTION:EuTiO3 is a cubic perovskite magnetoelectric combining spin an
 d charge degrees of freedom. The \nsystem has been shown to be a simultane
 ous low temperature antiferromagnet [1] and a soft \nmode type incipient f
 erroelectric [2]. A magnetoelectric coupling is present as evidenced by a 
 \nstrong enhancement of the dielectric constant with an applied magnetic f
 ield [3]. We report the \ndiscovery of a novel cubic to tetragonal structu
 ral phase transition and associate it with a soft \nphonon at the corner o
 f the cubic Brillouin zone. We provide a comparison with the 105K \ntransi
 tion in SrTiO3 and discuss the possible transition mechanisms accounting f
 or the \napproximately 100K difference in Ts present in these systems. We 
 further argue that EuTiO3 is an \nideal system in which to study quantum c
 ritical fluctuations of coupled charge and spin order \nparameters by tuni
 ng the transition temperature to absolute zero resulting in multiferroic \
 nquantum criticality. \n \nReferences: \n[1] T.R. McGuire\, et al.\, J. Ap
 pl. Phys 37\, 981 (1966) and references therein. \n[2] S. Kamba\, et al.\;
  Eur. Phys. Lett. 80\, 27002 (2007). \n[3] T.Katsufuji\, H.Takagi\, Phys. 
 Rev. B\, 64: 054415 (2001). 
LOCATION:Harker 2 lecture room\, Department of Earth Sciences\, Downing Si
 te
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