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Divergence of the orbital nuclear magnetic relaxation rate in metals

A. Knigavko·B. Mitrovic·K. V. Samokhin
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Abstract

We analyze the nuclear magnetic relaxation rate $(1/T_1)_{orb}$ due to the coupling of nuclear spin to the orbital moment of itinerant electrons in metals. In the clean non--interacting case, contributions from large--distance current fluctuations add up to cause a divergence of $(1/T_1)_{orb}$. When impurity scattering is present, the elastic mean free time $τ$ cuts off the divergence, and the magnitude of the effect at low temperatures is controlled by the parameter $\ln(μτ)$, where $μ$ is the chemical potential. The spin--dipolar hyperfine coupling, while has the same spatial variation $1/r^3$ as the orbital hyperfine coupling, does not produce a divergence in the nuclear magnetic relaxation rate.

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A. Knigavko, B. Mitrovic, K. V. Samokhin. 2007-02-22. Divergence of the orbital nuclear magnetic relaxation rate in metals. https://doi.org/10.1103/physrevb.75.134506

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