Sizable spin-transfer torque in the Bi/Ni80Fe20 bilayer film

Abstract

The search for efficient spin conversion in Bi has attracted great attention in spin-orbitronics. In the present work, we employ spin-torque ferromagnetic resonance to investigate spin conversion in Bi/Ni80Fe20(Py) bilayer films with continuously varying Bi thickness. In contrast with previous studies, sizable spin-transfer torque (i.e., a sizable spin-conversion effect) is observed in Bi/Py bilayer film. Considering the absence of spin conversion in Bi/yttrium-iron-garnet bilayers and the enhancement of spin conversion in Bi-doped Cu, the present results indicate the importance of material combinations to generate substantial spin-conversion effects in Bi.

Different spin relaxation property observed in linearly and circularly polarized laser induced terahertz emission from Bi/Co bilayer

“…Conversion between electron spin and physical quantities, such as charge, light, heat, and phonon, is one of the fundamental principles that enable the generation and detection of the spin current [1][2][3][4]. To enhance the conversion efficiency for future spintronic devices, numerous studies have explored various materials, such as topological materials [5,6] and heavy metals (e.g., Pt, W, Ta, and Bi [7][8][9][10][11][12]). In particular, Bi is the basis of several topological materials, such as Bi 0.9 Sb 0.1 , PtBi 2 , and Bi x Se 1−x [13][14][15].…”