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SUMMARY:Controlling the magnetic state with electricity - Dr Andrew Fergus
 on\, Microelectronics\, Cavendsh Laboratory
DTSTART:20130206T150000Z
DTEND:20130206T160000Z
UID:TALK43413@talks.cam.ac.uk
CONTACT:Leona Hope-Coles
DESCRIPTION:The magnetisation of a uniform spin-orbit coupled ferromagnet 
 can be controlled by an electrical current. This spin-orbit torque phenome
 non was predicted by theory [1\,2] and has been observed in the ferromagne
 tic semiconductor (Ga\,Mn)As [3\,4]. Controversial experiments report spin
 -orbit torques in multilayers of ferromagnetic metals [5\,6].\nI will desc
 ribe how the magnetisation of (Ga\,Mn)As responds to a microwave electrica
 l current. By electrically exciting ferromagnetic resonance\, it is possib
 le to reveal the spin-orbit torque vector [4]. Our experiments aim to unde
 rstand the symmetries involved and to demonstrate the ‘spin-orbit dynamo
 ’ effect: the precessing magnetisation in such a ferromagnetic layer is 
 predicted to drive an electrical current. I will argue that studying the (
 Ga\,Mn)As model system is essential for the understanding of spin-orbit to
 rques in ferromagnetic metal multilayers.\nMotivated by the theoretical li
 terature (e.g. [7]) on current induced effects in antiferromagnets\, as we
 ll as by the potential importance of these materials\, I plan to translate
  my group’s work on current induced dynamics in ferromagnets to antiferr
 omagnetic materials. Controlling\, and measuring\, the antiferromagnetic s
 tate with electricity poses considerable technical and material challenges
 . I detail experimental plans and motivations in this area.\n[1]  I. Garat
 e and A. H. MacDonald\, Phys. Rev. B 80\, 134403 (2009).\n[2]  A. Manchon 
 and S. Zhang\, Phys. Rev. B 79\, 094422 (2009).\n[3] A. Chernyshov\, M. Ov
 erby\, X. Liu\, J. K. Furdyna\, Y. Lyanda-Geller\, and L. P. Rokhinson\, N
 ature Phys. 5\, 656 (2009).\n[4] D. Fang\, H. Kurebayashi\, J. Wunderlich\
 , K. Vyborny\, L. P. Zarbo\, R. P. Campion\, A. Casiraghi\, B. L. Gallaghe
 r\, T. Jungwirth\, and A. J. Ferguson\, Nature Nanotech. 6\, 413 (2011).\n
 [5] I. M. Miron\, G. Gaudin\, S. Auffret\, B. Rodmacq\, A. Schuhl\, S. Piz
 zini\, J. Vogel and P. Gambardella Nat. Mater. 9\, 230 (2010).\n[6] I. M. 
 Miron\, K. Garello\, G. Gaudin\, P-J. Zermatten\, M. V. Costache\, S. Auff
 ret\, S. Bandiera\, B. Rodmacq\, A. Schuhl and P. Gambardella\, Nature 476
 \, 189 (2011).\n[7]  P. M. Haney and A. H. MacDonald\, Phys. Rev. Lett. 10
 0\, 196801 (2008).\n
LOCATION:Pippard Lecture Theatre\, Cavendish Laboratory\, Department of Ph
 ysics
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