Unconventional views on orbitronics supported by experimental results
Melissa Yactayo, A. Pezo, J. L. Ampuero, M. Tian, L. Badie, J. Quispe-Marcatoma, C. V. Landauro, Y. Xu, Sébastien Petit-Watelot, Michel Hehn, A. Fert, J. -C. Rojas-Sánchez
Abstract
Emerging orbitronics assumes long-range orbital current transport, analogous to spin currents. However, recent theory and experiments challenge this view, showing rather local characters for orbital polarization and orbit-spin conversions. We study angular momentum generated by ferromagnetic resonance and thermal gradients in Ni/(Pt)Ti/Au heterostructures. The observed charge current produced is independent of Ti thickness up to 60 nm, incompatible with orbital transport in Ti. Instead, its magnitude depends on both Ti interfaces, evidencing spin-mediated transport in between after and before local orbit-spin interconversions.