Scattering of spin current injected in Pd(001)

Abstract

We have studied spin pumping in Pd/ Fe͑001͒ ultrathin crystalline films prepared on GaAs͑001͒ by ferromagnetic resonance ͑FMR͒. FMR measurements show that the Pd͑001͒ overlayers lead to an appreciable attenuation of the spin current, which was generated by the precessing magnetization of Fe. Pd overlayers thicker than about 10 nm act as perfect spin sinks. It is argued that the loss of spin coherence in Pd is caused by scattering with spin fluctuations.

Spin-scattering rates in metallic thin films measured by ferromagnetic resonance damping enhanced by spin-pumping

“…The reported data for sf  in Pt and Pd span a significant range (0.5 to 14 nm for Pt [19,46,47], 2 to 12 nm for Pd [36,44,48,49,50], with several reported values smaller than the commonly-assumed mean-free-path for these materials.…”

“…At face value, the implication of the procedure used in Ref. [42] would appear to explain various experimental data that suggest sf   for samples where the NM thickness is comparable to, or even smaller than, the bulk-value for [36,44]. If  and, therefore,  are sufficiently reduced at small NM thicknesses, then it is possible that This would satisfy 5 an important requirement for the application of diffusion theory for spin transport in nonferromagnetic metals.…”

“…An alternative explanation rests on the fact that Pt and Pd are "almost" ferromagnetic according to Stoner theory [52]. As such, Pt and Pd are magnetically polarized when in direct contact with a ferromagnet [53,54], which could affect the spin-diffusion length, and even the functional form of spin-transport [44,50].…”

Spin pumping and the inverse spin hall effect in single crystalline Fe/Pt heterostructure

“…As the spin current generated in the adjacent layer, the damping of ferromagnetic material will be enhanced, 2-7 and the enhanced damping can be used to extract the spin diffusion length and the spin mixing conductance. [2][3][4][5][6][7] Moreover, the spin current in the heavy normal metal (NM) can be converted to a charge current through the inverse spin hall effect (ISHE). 8 The ISHE has been broadly studied, [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] and in general ferromagnetic metal (FM)/NM system, the ISHE is mixing with the spin rectification effect (SRE), which is induced by the anisotropic magneto-resistance (AMR).…”

Experimental Demonstration of Room-Temperature Spin Transport inn-Type Germanium Epilayers

“…where l Py ¼ 900 μm is the length of the Py strip, d Pd ¼ 10 nm is the thickness of the Pd strip, and θ SHE ¼ 0.01 [42] and λ Pd ¼ 9 nm [54] are the spin-Hall angle and the spin diffusion length of the Pd strip, respectively. By equating Eq.…”