We use lateral spin valves with varying interface resistance to measure non-local Hanle effect in order to extract the spin-diffusion length of the non-magnetic channel. A general expression that describes spin injection and transport, taking into account the influence of the interface resistance, is used to fit our results. Whereas the fitted spin-diffusion length value is in agreement with the one obtained from standard non-local measurements in the case of a finite interface resistance, in the case of transparent contacts a clear disagreement is observed. The use of a corrected expression, recently proposed to account for the anisotropy of the spin absorption at the ferromagnetic electrodes, still yields a deviation of the fitted spin-diffusion length which increases for shorter channel distances. This deviation shows how sensitive the non-local Hanle fittings are, evidencing the complexity of obtaining spin transport information from such type of measurements.
References
Py is a soft magnetic material; therefore, when starting from an initial AP state, the magnetization of one of the electrodes was always swiped back into the P state in the presence of a high enough BZ, preventing us from measuring RNL at the AP state for the whole range of BZ.
The effect of the nearby electrodes is considered due to the design of our devices, which consist of several LSVs on a row. However, by systematically varying the distance of the nearby Py/Cu LSVs with transparent interfaces, the same behaviour as in Fig. 2(a) is observed,16 ruling out any effect coming from the adjacent electrodes.
