2009 APS March Meeting
Volume 54, Number 1
Monday–Friday, March 16–20, 2009;
Pittsburgh, Pennsylvania
Session T22: Focus Session: GaMnAs
2:30 PM–5:30 PM,
Wednesday, March 18, 2009
Room: 324
Sponsoring
Units:
GMAG DMP FIAP
Chair: Nitin Samarth, Penn State University
Abstract ID: BAPS.2009.MAR.T22.1
Abstract: T22.00001 : Electric-field manipulation of magnetization vector direction*
2:30 PM–3:06 PM
Preview Abstract
Abstract
Author:
Hideo Ohno
(RIEC, Tohoku University / ERATO JST)
Ferromagnetism and magnetization in Mn-doped III-V
semiconductors can be manipulated by various means; by changing
its carrier concentration by electric fields [1] or by spin-
current flowing along with the electric current [2]. This
material system is thus an excellent system to study the
physics involved in manipulation of magnetism as well as
exploring new ways to control magnetization. Here, we show that
electrical control of magnetization direction can be done
through manipulating electronically the magnetic anisotropy
energies [3]. The basic idea behind the effort is to control
the population of carriers on spin-split anisotropic valence
bands that governs the magnetic anisotropy energies, which
should result in change of the direction of magnetization. In
order to measure the magnetic anisotropies under a gate that
applies the electric-field to the ferromagnetic semiconductor
channel, we used the planar Hall effect. Analyses showed that
there are biaxial as well as uniaxial anisotropies. As the
sheet carrier concentration is reduced by applying electric-
field to the channel, the uniaxial anisotropy field reduced its
magnitude and eventually changed its sign, whereas no
significant change was apparent in the biaxial anisotropy
field. From the electric-field dependent anisotropy fields, one
can show that the angle of the magnetization direction in the
absence of magnetic fields is modulated by electric-fields by
10 degrees. This opens up a new and unique opportunity for
manipulating magnetization direction solely by electronic
means, not resorting to magnetic-field, spin-current,
mechanical stress, nor multiferroics. The conditions for
switching the magnetization direction will also be discussed.
The work was done together with D. Chiba, F. Matsukura, M.
Sawicki, Y. Nishitani, and Y. Nakatani.
\\[4pt]
[1] H. Ohno, et al. Nature 408, 944 (2000). D. Chiba, et al.
Science, 301, 943 (2003). D. Chiba, et al. Appl. Phys. Lett.
89, 162505 (2006). \\[0pt]
[2] M. Yamanouchi, et al. Nature 428, 539
(2004). M. Yamanouchi, et al. Phys. Rev. Lett. 96, 096601
(2006). M. Yamanouchi, et al. Science 317, 1726, (2007). \\[0pt]
[3] D. Chiba, et al. Nature 455, 515 (2008).
*The word was supported in part by the ``Research and Development for Next-Generation Information Technology" program from MEXT, Japan.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.MAR.T22.1