2009 APS March Meeting
Volume 54, Number 1
Monday–Friday, March 16–20, 2009;
Pittsburgh, Pennsylvania
Session V7: Applications of Magnetic Thin Films with Tilted Anisotropy
8:00 AM–10:24 AM,
Thursday, March 19, 2009
Room: 407
Sponsoring
Unit:
GMAG
Chair: Johan Ã…kerman, Royal Institute of Technology, Sweden
Abstract ID: BAPS.2009.MAR.V7.4
Abstract: V7.00004 : Spin-torque oscillators with tilted fixed layer magnetization
9:48 AM–10:24 AM
Preview Abstract
Abstract
Author:
Chaolin Zha
(Department of Microelectronics and Applied Physics, Royal Institute of Technology, Sweden)
One of the promising applications based on the spin transfer
effect [1-3] is
the Spin Torque Oscillator (STO) with signal generation at microwave
frequencies related to ferromagnetic resonance. The STO may be
thought of as
a nanoscopic Yttrium Iron Garnet (YIG) oscillator with a
similarly broad
frequency range, but significant advantages such as easy on-chip
integration, and current tunability instead of only field
tunability.
However, STOs still typically require a large, static, magnetic
field for
operation; removing the need for this field is currently an
intensely
researched topic.
Three different STO designs have been attempted to address zero
field
operation: $i)$ the perpendicularly polarized STO [4],
\textit{ii}) the wavy torque STO
[5], and \textit{iii}) the vortex STO [6]. Recently we proposed
the Tilted Polarizer STO
(TP-STO) having a fixed layer with an out-of-plane magnetic
easy-axis tilted
a finite angle away from the film normal [7]. In this talk, I
will review
our simulation work of the TP-STO and show its potential to
generate large
output signal in zero field. I will present detailed structural
and magnetic
characterization of single layer L1$_{0}$ (111) FePt with tilted
magnetic
anisotropy and show how we have fabricated FePt/Cu/NiFe pseudo
spin valves
with magnetoresistance values of about 0.5{\%}, and as much as
5{\%} if each
interface is dusted with CoFe. Finally, I will present our
preliminary work
on observing actual microwave signal generation in nano-contact
TP-STOs and
discuss their potential for applications.
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References
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[1] J. C. Slonczewski, J. Magn. Magn. Mater. 159, 1 (1996).
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[2] L. Berger, Phys. Rev. B 54, 9353 (1996).
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[3] J. A. Katine,et al., Phys. Rev. Lett. 84, 3149 (2000).
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[4] D. Houssameddine, et al, Nat. Mater. 6, 447 (2007).
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[5] O. Boulle, et al., Nat. Phys. 3, 492 (2007).
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[6] V. S. Pribiag, et al., Nat. Phys. 3, 498 (2007).
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[7] Yan Zhou, et al, Appl. Phys. Lett. 92, 262508 (2008); idem,
accepted, J.
Appl. Phys., (2009).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.MAR.V7.4