Spin Pumping Induced Electric Voltage

Spin pumping in a ferromagnetic (FM) and nonmagnetic (NM) metallic bilayer generates an electric voltage whose origins have been attributed to the inverse spin Hall effect (ISHE) in the NM layer. We show that the electric voltage or current from the spin pumping is not limited to the ISHE of the NM layer; instead, there are two other previously unidentified contributions: one from the interface and the other from the FM layer. By using our newly developed spin pumping formalism, we compute the relative contributions of these three sources of the induced electric voltages. When we apply our results to a NiFe/Pt bilayer, we find the contribution from the strong spin-orbit coupled interface, known as the inverse Edelstein effect (IEE), can be as large as or even larger than that from the NM layer. Our finding indicates that the experimental estimation of the spin Hall angle and spin diffusion length of Pt should include both IEE and ISHE.

[1]  Eiji Saitoh,et al.  Conversion of spin current into charge current at room temperature: Inverse spin-Hall effect , 2006 .

[2]  G. Vignale,et al.  Microscopic theory of the inverse Edelstein effect. , 2013, Physical review letters.

[3]  Gerrit E W Bauer,et al.  Spin backflow and ac voltage generation by spin pumping and the inverse spin Hall effect. , 2013, Physical review letters.

[4]  R Urban,et al.  Gilbert damping in single and multilayer ultrathin films: role of interfaces in nonlocal spin dynamics. , 2001, Physical review letters.

[5]  P. Hyde,et al.  Electrical Detection of Direct and Alternating Spin Current Injected from a Ferromagnetic Insulator into a Ferromagnetic Metal , 2013, 1310.4840.

[6]  R. Takahashi,et al.  Geometry dependence on inverse spin Hall effect induced by spin pumping in Ni 81 Fe 19 /Pt films , 2012 .

[7]  A. Hoffmann.  Spin Hall Effects in Metals , 2013, IEEE Transactions on Magnetics.

[8]  A. Brataas,et al.  Enhanced gilbert damping in thin ferromagnetic films. , 2001, Physical review letters.

[9]  R. Loloee,et al.  Spin-memory loss at 4.2 K in sputtered Pd and Pt and at Pd/Cu and Pt/Cu interfaces , 2002 .

[10]  Spin transport parameters in metallic multilayers determined by ferromagnetic resonance measurements of spin pumping , 2013, 1301.5861.

[11]  J. Pearson,et al.  Determination of the Pt spin diffusion length by spin-pumping and spin Hall effect , 2013 .

[12]  L. Sun,et al.  Spin Hall angle quantification from spin pumping and microwave photoresistance , 2012, 1203.6175.

[13]  M. D. Stiles,et al.  Anatomy of spin-transfer torque , 2002 .

[14]  A. Fert,et al.  Spin-to-charge conversion using Rashba coupling at the interface between non-magnetic materials , 2013, Nature Communications.

[15]  J. Pearson,et al.  Quantifying spin Hall angles from spin pumping: experiments and theory. , 2009, Physical review letters.

[16]  H. Jaffrès,et al.  Spin pumping and inverse spin Hall effect in platinum: the essential role of spin-memory loss at metallic interfaces. , 2013, Physical review letters.

[17]  E. Goovaerts,et al.  Spin transport parameters in Ni_{80}Fe_{20}/Ru and Ni_{80}Fe_{20}/Ta bilayers , 2014 .

[18]  Timo Kuschel,et al.  Quantitative study of the spin Hall magnetoresistance in ferromagnetic insulator/normal metal hybrids , 2013, 1304.6151.

[19]  G. Woltersdorf,et al.  Gilbert Damping in Single and Multilayer Ultrathin Films , 2001 .

[20]  Sergio M. Rezende,et al.  dc effect in ferromagnetic resonance: Evidence of the spin-pumping effect? , 2005 .

[21]  Aurelien Manchon,et al.  Nonequilibrium intrinsic spin torque in a single nanomagnet , 2008 .

[22]  N. Vlietstra,et al.  Platinum thickness dependence of the inverse spin-Hall voltage from spin pumping in a hybrid yttrium iron garnet/platinum system , 2012, 1206.7080.

[23]  Self-induced inverse spin Hall effect in permalloy at room temperature , 2013, 1301.3580.

[24]  S. Maekawa,et al.  Angular dependence of inverse spin-Hall effect induced by spin pumping investigated in a Ni 81 Fe 19 /Pt thin film , 2008 .

[25]  Shufeng Zhang,et al.  Spin pumping in the presence of spin-orbit coupling. , 2015, Physical review letters.