2026-09-20T07:57:40Zhttps://ecommons.cornell.edu/server/oai/requestoai:ecommons.cornell.edu:1813/310262026-05-14T13:50:47Zcom_1813_35col_1813_47
Ryan, Eric
Buhrman, Robert A
Van Dover, Robert B.
McEuen, Paul L.
2013-01-31T19:43:58Z
2017-12-20T07:00:28Z
2012-08-20
https://hdl.handle.net/1813/31026
7959739
In this thesis, we fabricate magnetic nanopillars and dramatically enhance their damping through terbium doping in order to suppress the various spin-transfer effects, to the potential benefit of magnetic hard drive read head technology. This enhancement is much stronger at lower temperatures, and we can understand the 1/T temperature dependence observed through the application of established theory from the iron garnets. We also show that terbium doping can address technological problems with hard drive read heads. In particular, by inhibiting the microwave noise until a higher turn-on current is reached, without compromising the ability of the device to switch with reasonable power in times scales as short as 1 nsec, terbium-doped structures point the way forward for future designs. Finally, we make direct FMR measurements of the Gilbert phenomenological damping parameter at the center of these effects, and these measurements also suggest cobalt-iron alloys as systems for potential follow-up work.
en_US
spin-transfer
terbium
magnetic
hard drive read head
nanopillar
damping
temperature
doping
Critical Current Enhancement In Magnetic Spin-Transfer Nano-Devices Through Doping With The Rare Earth Terbium
dissertation or thesis
application/pdf
Applied Physics
Cornell University
Doctor of Philosophy
Ph. D., Applied Physics
Publication
Cornell Theses and Dissertations
Ryan, Eric
5893a6ea-7af3-41d7-abc6-04bcd26ab5df
open.access
open.access
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<Abstract>In this thesis, we fabricate magnetic nanopillars and dramatically enhance their damping through terbium doping in order to suppress the various spin-transfer effects, to the potential benefit of magnetic hard drive read head technology. This enhancement is much stronger at lower temperatures, and we can understand the 1/T temperature dependence observed through the application of established theory from the iron garnets. We also show that terbium doping can address technological problems with hard drive read heads. In particular, by inhibiting the microwave noise until a higher turn-on current is reached, without compromising the ability of the device to switch with reasonable power in times scales as short as 1 nsec, terbium-doped structures point the way forward for future designs. Finally, we make direct FMR measurements of the Gilbert phenomenological damping parameter at the center of these effects, and these measurements also suggest cobalt-iron alloys as systems for potential follow-up work.</Abstract>
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