1205.4565 (D. Kölbl et al.)

Breakdown of the Korringa Law of Nuclear Spin Relaxation in Metallic
GaAs    [PDF]

D. Kölbl, D. M. Zumbühl, A. Fuhrer, G. Salis, S. F. Alvarado

We present nuclear spin relaxation measurements in GaAs epilayers using a new pump-probe technique in all-electrical, lateral spin-valve devices. The measured $T_1$ times agree very well with NMR data available for $T>$\,1\,K. However, the nuclear spin relaxation rate clearly deviates from the well-established Korringa law expected in metallic samples and follows a sub-linear temperature dependence $T_1^{-1} \propto T^{0.6}$ for 0.1 K $\leq T \leq$ 10 K. Further, we investigate nuclear spin inhomogeneities.

View original: http://arxiv.org/abs/1205.4565