Inverse Spin Hall Effect in Electron Beam Evaporated Topological Insulator Bi2Se3 Thin Film

• Published in: Physica status solidi. PSS-RRL. Rapid research letters Vol. 13; no. 3
• Main Authors: Singh, Braj B., Jena, Sukanta K., Samanta, Manisha, Biswas, Kanishka, Satpati, Biswarup, Bedanta, Subhankar
• Format: Journal Article
• Language: English
• Published: Berlin WILEY?VCH Verlag Berlin GmbH 01.03.2019; Wiley Subscription Services, Inc
• Subjects: Bilayers; Dependence; Electric potential; Electrical measurement; Electromagnetism; Electron beams; Electron spin; Ferromagnetic materials; ferromagnetic resonance; Hall effect; Heavy metals; inverse spin Hall effect; Magnetic fields; Magnetism; Magnetoresistance; Magnetoresistivity; Momentum; Pumping; Silicon substrates; spin pumping; Spin-orbit interactions; Spintronics; Tantalum; Thin films; topological insulator/ferromagnetic interface; Topological insulators
• ISSN: 1862-6254; 1862-6270
• DOI: 10.1002/pssr.201800492

Spintronics exploiting pure spin current in ferromagnetic (FM)/heavy metals (HM) is a subject of intense research. Topological insulators having spin momentum locked surface states exhibit high spin–orbit coupling and thus possess a huge potential to replace the HM like Pt, Ta, W, etc. In this context, the spin pumping phenomenon in Bi2Se3/CoFeB bilayers has been investigated. Bi2Se3 thin films are fabricated by electron beam evaporation method on Si (100) substrate. In order to confirm the topological nature of Bi2Se3, low temperature magnetotransport measurement on a 30 nm thick Bi2Se3 film which shows 10% magnetoresistance (MR) at 1.5 K has been performed. A linear increase in MR with applied magnetic field indicates the presence of spin momentum‐locked surface states. A voltage has been measured at room temperature to quantify the spin pumping which is generated via inverse spin Hall effect (ISHE). For the separation of spin rectification effects mainly produced by the FM CoFeB layer, in plane angular dependence of the dc voltage with respect to applied magnetic field has been measured. Our analysis reveals that spin pumping induced ISHE is the dominant contribution in the measured voltage. Bi2Se3 thin film has been prepared by electron beam evaporation. Its magnetoresistance shows comparable value to Bi2Se3 films prepared by molecular beam epitaxy. Inverse spin Hall effect (ISHE) is observed predominantly due to spin pumping in Bi2Se3/CoFeB bilayers. Angle‐dependent measurements are performed to disentangle different spin rectification effects.