Phase-resolved x-ray ferromagnetic resonance measurements of spin pumping in spin valve structures

Marcham, M. K.; Shelford, L. R.; Cavill, S. A.; Keatley, P. S.; Yu, W.; Shafer, P.; Neudert, A.; Childress, J. R.; Katine, J. A.; Arenholz, E.; Telling, N. D.; van der Laan, G.; Hicken, R. J.

Abstract

Element-specific phase-resolved x-ray ferromagnetic resonance (FMR) was used to study spin pumping within Co
50
Fe
50
(3)/Cu(6)/Ni
80
Fe
20
(5) (thicknesses in nanometers) spin valve structures with large areas, so that edge effects typical of nanopillars used in standard magnetotransport experiments could be neglected. The phase of precession of the Co
50
Fe
50
fixed layer was recorded as FMR was induced in the Ni
80
Fe
20
free layer. The field dependence of the fixed layer phase contains a clear signature of spin transfer torque (STT) coupling due to spin pumping. Fitting the phase delay yields the spin-mixing conductance, the quantity that controls all spin transfer phenomena. The STT coupling is destroyed by insertion of Ta into the middle of the Cu layer.

• Journal Article Type: Article
• Online Publication Date: May 21, 2013
• Publication Date: 2013-05
• Deposit Date: Jun 12, 2023
• Journal: Physical Review B
• Print ISSN: 1098-0121
• Electronic ISSN: 1550-235X
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 87
• Issue: 18
• DOI: https://doi.org/10.1103/physrevb.87.180403
• Keywords: Condensed Matter Physics; Electronic, Optical and Magnetic Materials