Reliability of spin-to-charge conversion measurements in graphene-based\n lateral spin valves

Abstract

Understanding spin physics in graphene is crucial for developing future\ntwo-dimensional spintronic devices. Recent studies show that efficient\nspin-to-charge conversions via either the inverse spin Hall effect or the\ninverse Rashba-Edelstein effect can be achieved in graphene by proximity with\nan adjacent spin-orbit coupling material. Lateral spin valve devices, made up\nof a graphene Hall bar and ferromagnets, are best suited for such studies.\nHere, we report that signals mimicking the inverse Rashba-Edelstein effect can\nbe measured in pristine graphene possessing negligible spin-orbit coupling,\nconfirming that these signals are unrelated to spin-to-charge conversion. We\nidentify either the anomalous Hall effect in the ferromagnet or the ordinary\nHall effect in graphene induced by stray fields as the possible sources of this\nartefact. By quantitatively comparing these options with finite-element-method\nsimulations, we conclude the latter better explains our results. Our study\ndeepens the understanding of spin-to-charge conversion measurement schemes in\ngraphene, which should be taken into account when designing future experiments.\n