2,018 research outputs found
Spin-Wave Relaxation in a Quantum Hall Ferromagnet
We study spin wave relaxation in quantum Hall ferromagnet regimes. Spin-orbit
coupling is considered as a factor determining spin nonconservation, and
external random potential as a cause of energy dissipation making spin-flip
processes irreversible. We compare this relaxation mechanism with other
relaxation channels existing in a quantum Hall ferromagnet.Comment: Submitted to JETP Letter
Feeding ecology of sprat (Sprattus sprattus L.) and sardine (Sardina pilchardus W.) larvae in the German Bight, North Sea
The abundance of the sardine in the North Sea suddenly increased after 1995. Since 2002, the sardine has been spawning regularly in the German Bight, and all its life stages can be found in the area. The larval feeding ecology of two small pelagic clupeiform species with very similar life histories was investigated, the particular aim being to determine signs of food overlap. The distribution and feeding of sprat and sardine larvae were investigated during late spring 2003 on two transects covering a wide range of environmental conditions in the German Bight. Larvae co-occurred at all the stations investigated. Sprat and sardine larvae shared a wide range of prey types. Gut fullness and feeding success were similar in both species; however, potential food competition is avoided to some extent by different habitat preferences
Collective excitations in a magnetically doped quantized Hall ferromagnet
A theory of collective states in a magnetically quantized two-dimensional
electron gas (2DEG) with half-filled Landau level (quantized Hall ferromagnet)
in the presence of magnetic 3d impurities is developed. The spectrum of bound
and delocalized spin-excitons as well as the renormalization of Zeeman
splitting of the impurity 3d levels due to the indirect exchange interaction
with the 2DEG are studied for the specific case of n-type GaAs doped with Mn
where the Lande` g-factors of impurity and 2DEG have opposite signs. If the
sign of the 2DEG g-factor is changed due to external influences, then impurity
related transitions to new ground state phases, presenting various spin-flip
and skyrmion-like textures, are possible. Conditions for existence of these
phases are discussed. PACS: 73.43.Lp, 73.21.Fg, 72.15.RnComment: 32 pages including 7 figures. To be published in Phys. Rev.
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