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AM: Magnetismus
AM 3: Magnetowiderstand I
AM 3.2: Talk
Monday, March 26, 2001, 14:45–15:00, S 5.2
Dissipationless Spin Transport in Thin Film Ferromagnets — •Jürgen König1,2, Martin Bønsager2, and Allan MacDonald1,2 — 1Department of Physics, University of Texas, Austin, USA — 2Department of Physics, Indiana University, Bloomington, USA
In ferromagnetic metals and semiconductors quasiparticle states can be manipulated by external magnetic fields that couple to the spin-magnetization-density collective coordinate. This property is responsible for magnetoresistance effects such as anisotropic magnetoresistance, giant magnetoresistance, and tunnel magnetoresistance.
We propose [1] a distinctly different type of spin-dependent transport effect, which is also dependent on ferromagnetic order, but in which the spin current is carried collectively rather than by quasiparticles. Because the spin current is non-zero when its quasiparticles are in equilibrium, it is carried without dissipation. This spin-supercurrent state occurs only in easy-plane ferromagnets. We propose an experiment to prepare it and detect its presence in thin film ferromagnets.
[1] J. König, M.C. Bønsager, and A.H. MacDonald, cond-mat/0011504, submitted to PRL.