Jiménez Cavero, PilarLucas, IreneBugallo Ferrón, DavidLópez Bueno, CarlosRamos Amigo, Rafael EnriqueAlgarabel, Pedro AntonioIbarra, Manuel RicardoRivadulla Fernández, José FranciscoMorellón, Luis2021-03-152021-03-152021Appl. Phys. Lett. 118, 092404 (2021); https://doi.org/10.1063/5.00381920003-6951http://hdl.handle.net/10347/24752This article appeared in P. Jiménez-Cavero et al. Applied Physics Letters 118, 092404 (2021) and may be found at https://aip.scitation.org/doi/10.1063/5.0038192We report the disentanglement of bulk and interfacial contributions to the thermally excited magnon spin current in the spin Seebeck effect under static heating. For this purpose, we have studied the dependence of the inverse spin Hall voltage and the thermal conductivity on the magnetic layer thickness. Knowledge of these quantities allows us to take into account the influence of both sources of thermal spin current in the analysis of the voltage dependence. The magnetic layer thickness modulates the relative magnitude of the involved thermal drops for a fixed total thermal difference throughout the sample. In the end, we attain the separate contributions of both sources of thermal spin current—bulk and interfacial—and obtain the value of the thermal magnon accumulation length scale in maghemite, which we find to be 29(1) nm. According to our results, bulk magnon accumulation dominates the spin Seebeck effect in our studied range of thicknesses, but the interfacial component is by no means negligibleeng© 2021 Author(s). Published under license by AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishingjournal article10.1063/5.00381921077-3118open access