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SUMMARY:Probing Magnetocaloric Effect in Magnetic Topological Insulator - 
 Shu-Wei Wang\, Cavendish Laboratory\, University of Cambridge\, UK
DTSTART:20180314T140000Z
DTEND:20180314T150000Z
UID:TALK102943@talks.cam.ac.uk
CONTACT:Dr Kaveh Delfanazari
DESCRIPTION:\n    Ferromagnetic exchange in magnetically-doped topological
  insulators (TI) can break time-reversal symmetry and open a gap in the qu
 asiparticle Dirac spectrum of the two-dimensional surface states. The quan
 tum anomalous Hall (QAH) effect can be observed when the Fermi level is in
 side the exchange gap [1-2]. In addition\, tuning the Fermi level out of t
 he exchange gap repopulates the surfaces\, resulting in changes in tempera
 ture with magnetization that can be considerable at millikelvin temperatur
 es [3]. We study this magnetocaloric effect by performing magnetization lo
 ops while simultaneously monitoring the resistance and temperature of the 
 (Bi0.29Sb0.71)1.89V0.11Te3 films. We find that sweeping the external magne
 tic field beyond the coercive field of the film and then back to zero fiel
 d lowers the sample temperature. The possible origin of the cooling is the
  magnetocaloric effect from the film. In the demagnetization process the f
 ilm can reach a temperature below the base temperature of the dilution ref
 rigerator.\n
LOCATION:Mott Seminar Room (Mott Building Room 531)\, Cavendish Laboratory
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