Topological materials are of high interest due to the promise to obtain low power and fast memory devices based on efficient spin-orbit torque switching or spin-orbit magnetic state read-out. In particular, sputtered polycrystalline ${\mathrm{Bi}}_x{\mathrm{Se}}_{1-x}$ is one of the materials with more potential for this purpose since it is relatively easy to fabricate and has been reported to have a very high spin Hall angle. We study the spin-to-charge conversion in ${\mathrm{Bi}}_x{\mathrm{Se}}_{1-x}$ using the spin-pumping technique coming from the ferromagnetic resonance in a contiguous permalloy thin film. We put a special emphasis on the interfacial properties of the system. Our results show that the spin Hall angle of ${\mathrm{Bi}}_x{\mathrm{Se}}_{1-x}$ has the same sign as the one of Pt. The charge current arising from the spin-to-charge conversion is, in contrast, lower than Pt by more than one order of magnitude. We ascribe this to the interdiffusion of ${\mathrm{Bi}}_x{\mathrm{Se}}_{1-x}$ and permalloy and the changes in chemical composition produced by this effect, which is an intrinsic characteristic of the system and is not considered in many other studies.

Close

PrevNext

View figure in article

• Composition
• Growth
• Magnetism
• Magnetization dynamics
• Polycrystals
• Spintronics
• Topological insulators