Dephasing in ferromagnets: The role of spin waves – Niels Bohr Institute - University of Copenhagen

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Niels Bohr Institute > Calendar > 2012 > Dephasing in ferromagn...

Dephasing in ferromagnets: The role of spin waves

If a metallic sample is smaller than the typical electronic phase braking length, then one can usually observe signatures of quantum coherence in its transport properties, such as weak localization, Aharonov-Bohm oscillations, and universal conductance fluctuations. For the case of normal metals, these phenomena, as well as the main mechanisms of dephasing destroying them, have been intensively investigated in the past few decades, and are by now well understood. In ferromagnets however, experiments often indicate dephasing rates which are by far too large to fit the “standard” theory. But indeed, besides all processes known from normal metals, one could think of extra dephasing mechanisms playing a role in ferromagnets: spin-flip scattering in the presence of an exchange splitting, interaction with spin waves, and interaction with domain walls.

In this talk, I will present a calculation of the dephasing rate of electrons in a ferromagnet relevant for the conductance fluctuations, and focusing on the contribution from the interaction with spin waves.
Explicit results are presented for quasi-one-dimensional systems. Going beyond previous work, our calculation is not restricted to the limit of a small exchange splitting compared to the electronic elastic scattering time, nor does it rely on the diffusion approximation to describe electronic transport.

Talk by Jeroen Danon