Second, magnetic anisotropy can also be generated by coherent transport processes, resulting in a proximity effect, much like that responsible for the well-known (dipolar) exchange field, an effective magnetic field which allows for control over a spin-1/2 quantum dot spin-valves, even in the time-domain. The most dramatic illustration of this kind of "quadrupolar proximity effect" is the generation "from scratch" of a magnetic anisotropy term in the effective Hamiltonian of a spin-1 quantum dot. This turns an isotropic spin-1 system into a full-blown single-molecule magnet with electrically controllable magnetic bistability. The magnitude of the proximity-induced spin-reversal barrier can match that of state-of-the art single-molecule magnets."> Second, magnetic anisotropy can also be generated by coherent transport processes, resulting in a proximity effect, much like that responsible for the well-known (dipolar) exchange field, an effective magnetic field which allows for control over a spin-1/2 quantum dot spin-valves, even in the time-domain. The most dramatic illustration of this kind of "quadrupolar proximity effect" is the generation "from scratch" of a magnetic anisotropy term in the effective Hamiltonian of a spin-1 quantum dot. This turns an isotropic spin-1 system into a full-blown single-molecule magnet with electrically controllable magnetic bistability. The magnitude of the proximity-induced spin-reversal barrier can match that of state-of-the art single-molecule magnets."> TUD, chair Cuniberti "materials science and nanotechnology" - Lehrstuhl Cuniberti "Materialwissenschaft und Nanotechnik"
Skip to content.

TUD

search  |  internal  |  deutsch
Personal tools
TU Dresden » Faculty of Mechanical Science and Engineering » Institute for Materials Science » Chair of Materials Science and Nanotechnology



Thursday , 16 October 2014
(at 13:00 in room HAL 115)
Add to your Google Calendar


Magnetic anisotropy goes spintronic

Maarten R. Wegewijs


Institute for Theory of Statistical Physics, RWTH Aachen University
   






Magnetic anisotropy of quantum spins as found in magnetic atoms and single-molecule magnets has traditionally been considered an intrinsic effect, generated locally by the combination of spin-orbit coupling and ligand field effects. In this talk I will show that magnetic anisotropy can, however, appear in a new way, as a transport quantity, even in a very simple a spin-isotropic quantum dot supporting a spin-1 which is exposed to the influence of magnetic electrodes. Much like spin-polarization transport, spin-anisotropy transport has two main aspects: First, magnetic anisotropy is shown to appear as a dissipative transport quantity which is able to "get stuck" in a system, quite similar to how spin accumulates in a spin-valve. This idea is made precise by continuity equations that relate accumulation of the spin-quadrupole moment tensor to corresponding currents. The latter new tensor-valued currents describe the flow of magnetic anisotropy, very similar to how spin-currents describe the flow of the vectorial quantity of spin-polarization. I will show how measurable charge transport in a quantum-dot spin-1 valve depends on this flow and accumulation of spin-anisotropy. Second, magnetic anisotropy can also be generated by coherent transport processes, resulting in a proximity effect, much like that responsible for the well-known (dipolar) exchange field, an effective magnetic field which allows for control over a spin-1/2 quantum dot spin-valves, even in the time-domain. The most dramatic illustration of this kind of "quadrupolar proximity effect" is the generation "from scratch" of a magnetic anisotropy term in the effective Hamiltonian of a spin-1 quantum dot. This turns an isotropic spin-1 system into a full-blown single-molecule magnet with electrically controllable magnetic bistability. The magnitude of the proximity-induced spin-reversal barrier can match that of state-of-the art single-molecule magnets.

Brief Bio:

2013 - apl Professor, RWTH Aachen University, Germany.
2013 - Permanent staff member, Peter Grüunberg Institute (PGI-2), Forschungszentrum Jülich, Germany.
2007-2013 Junior Professor, RWTH Aachen University, Germany.
2007-2013 Leader Helmholtz-University Young-Investigator Group (tenured), Forschungszentrum Jülich and RWTH Aachen University, Germany.
2005-2007 C1 Research assistant, RWTH Aachen University, Germany.
2002-2004 Young Researcher European Commission - Research Training Network Spintronics,RWTH Aachen University, Germany.
2001-2002 Post. Doc researcher, RWTH Aachen University, Germany.

Education
1997-2001 Ph.-D theoretical physics, TU Delft and DIMES, Delft, Netherlands.1991-1997 Applied physics, TU Delft, Delft, Netherlands.

Announcement (pdf)

Invited by G. Cuniberti

Within the nanoSeminar

last modified: 2017.11.15 Mi
author: webadmin

contact
Prof. Dr. Gianaurelio Cuniberti
secretariat:
Ms Sylvi Katzarow
phone: +49 (0)351 463-31420
fax: +49 (0)351 463-31422
office@nano.tu-dresden.de
postal address:
Institute for Materials Science
TU Dresden
01062 Dresden, Germany
visitors and courier address:
HAL building
TU Dresden
Hallwachsstr. 3
01069 Dresden, Germany
Max Bergmann Center
TU Dresden
Budapester Str. 27
01069 Dresden, Germany