Speaker
Dr
S R Dunsiger
(Physik Department, Technische Universität München, Garching, Germany)
Description
Technologically, a semiconductor which is also a ferromagnet has exciting potential for spintronic applications, where logic and memory operations could in principle be integrated on a single device. Artificial heterostructures based on such ferromagnets show immense promise, in particular for the injection of polarised spins into a semiconducting substrate. From a fundamental perspective, understanding ferromagnetism in a novel material which is also a semiconductor is an important challenge. Although no consensus on the mechanism has yet been reached, it is now established that the interaction between the magnetic atoms in prototypical systems like the III-V semiconducting materials Ga1−xMnxAs/GaAs or EuO1-x/doped Si is induced by charge carriers in the semiconductor host. Large changes in the electronic structure occur as the temperature is reduced through the Curie temperature, caused by an exchange splitting of the conduction band in the ferromagnetic state.
The unusual interplay between magnetism and transport properties opens up the interesting and potentially technologically useful possibility of modulating magnetic behaviour by controlling the charge carrier properties, through doping, applied electric fields or photoexcitation. These heterostructures may be produced in thin film form using non-equilibrium techniques such as molecular beam epitaxy. Investigations using local probes which are sensitive to magnetic structure on a nanometre lengthscale are therefore invaluable. I will discuss our recent studies of the internal magnetic field distribution and spin fluctuations in these model materials for spintronic devices using depth resolved Low Energy mu-SR and beta-detected Nuclear Magnetic Resonance (beta-NMR), complementary spin resonance techniques.
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Talk
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MOPS
Primary author
Dr
S R Dunsiger
(Physik Department, Technische Universität München, Garching, Germany)
Co-authors
Dr
A Schmehl
(Lehrstuhl für Experimentalphysik VI, Augsburg University, Augsburg, Germany)
Dr
A Sutter
(Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, Villigen, Switzerland)
Dr
D Chiba
(ERATO Semiconductor Spintronics Project, Japan Science and Technology Agency, Tokyo, Japan and Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan)
Dr
D G Schlom
(Materials Science and Engineering, Cornell University, New York, USA)
Prof.
E Morenzoni
(Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, Villigen, Switzerland)
Dr
F Matsukura
(ERATO Semiconductor Spintronics Project, Japan Science and Technology Agency, Tokyo, Japan and Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan)
Dr
G D Morris
(TRIUMF, Vancouver, Canada)
Dr
G Nieuwenhuys
(Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, Villigen, Switzerland)
Dr
H Ohno
(ERATO Semiconductor Spintronics Project, Japan Science and Technology Agency, Tokyo, Japan and Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan)
Dr
J Mannhart
(Max Planck Institute for Solid State Research, Stuttgart, Germany)
Dr
J Ohe
(Institute for Materials Research, Tohoku University, Sendai, Japan and CREST, Japan Science and Technology Agency (JST), Sanbancho, Tokyo, Japan)
Dr
J P Carlo
(Department of Physics, Columbia University, New York, USA)
Prof.
K H Chow
(Department of Physics, University of Alberta, Edmonton, Canada)
Prof.
P Böni
(Physik Department, Technische Universität München, Garching, Germany)
Dr
R F Kiefl
(Dept of Physics and Astronomy, University of British Columbia, Vancouver, Canada)
Dr
S Maekawa
(Institute for Materials Research, Tohoku University, Sendai, Japan and CREST, Japan Science and Technology Agency (JST), Sanbancho, Tokyo, Japan)
Dr
T Goko
(Department of Physics, University of Alberta, Edmonton, Canada)
Dr
T Prokscha
(Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, Villigen, Switzerland)
Dr
T Tanikawa
(ERATO Semiconductor Spintronics Project, Japan Science and Technology Agency, Tokyo, Japan and Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan)
Dr
W A MacFarlane
(Dept of Chemistry, University of British Columbia, Vancouver, Canada)
Dr
Y J Uemura
(Department of Physics, Columbia University, New York, USA)
Dr
Y Nishitani
(Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan)
