We study the impact of the magnetic field angle on the oscillation frequency of a nanocontact spin torque oscillator (STO) in magnetic fields up to 2.1 T. A model based on a single nonlinear, nonpropagating spin wave mode is found to explain the experimental data. We observe oscillation frequencies as high as 46 GHz in high magnetic fields applied normal to the film plane, and we are able to extrapolate the maximum expected operating frequency to beyond 65 GHz for in-plane magnetic fields. The STO signal remains surprisingly strong at these conditions, which opens up for possible millimeter-wave applications.
REFERENCES
1.
S. I.
Kiselev
, J. C.
Sankey
, I. N.
Krivorotov
, N. C.
Emley
, R. J.
Schoelkopf
, R. A.
Buhrman
, and D. C.
Ralph
, Nature (London)
425
, 380
(2003
).2.
W. H.
Rippard
, M. R.
Pufall
, S.
Kaka
, S. E.
Russek
, and T. J.
Silva
, Phys. Rev. Lett.
92
, 027201
(2004
a).3.
M.
Tsoi
, J. Z.
Sun
, and S. S. P.
Parkin
, Phys. Rev. Lett.
93
, 036602
(2004
).4.
S. I.
Kiselev
, J. C.
Sankey
, I. N.
Krivorotov
, N. C.
Emley
, M.
Rinkoski
, C.
Perez
, R. A.
Buhrman
, and D. C.
Ralph
, Phys. Rev. Lett.
93
, 036601
(2004
).5.
A.
Tulapurkar
, Y.
Suzuki
, A.
Fukushima
, H.
Kubota
, H.
Maehara
, K.
Tsunekawa
, D.
Djayaprawira
, N.
Watanabe
, and S.
Yuasa
, Nature (London)
438
, 339
(2005
).6.
S. I.
Kiselev
, J. C.
Sankey
, I. N.
Krivorotov
, N. C.
Emley
, A. G. F.
Garcia
, R. A.
Buhrman
, and D. C.
Ralph
, Phys. Rev. B
72
, 064430
(2005
).7.
Q.
Mistral
, J. -V.
Kim
, T.
Devolder
, P.
Crozat
, C.
Chappert
, J. A.
Katine
, M. J.
Carey
, and K.
Ito
, Appl. Phys. Lett.
88
, 192507
(2006
).8.
D.
Houssameddine
, U.
Ebels
, B.
Delaet
, B.
Rodmacq
, I.
Firastrau
, F.
Ponthenier
, M.
Brunet
, C.
Thirion
, J. -P.
Michel
, L.
Prejbeanu-Buda
, M. -C.
Cyrille
, O.
Redon
, and B.
Dieny
, Nature Mater.
6
, 447
(2007
).9.
O.
Boulle
, V.
Cros
, J.
Grollier
, L. G.
Pereira
, C.
Deranlot
, F.
Petroff
, G.
Faini
, J.
Barnas
, and A.
Fert
, Nat. Phys.
3
, 492
(2007
).10.
K. V.
Thadani
, G.
Finocchio
, Z. P.
Li
, O.
Ozatay
, J. C.
Sankey
, I. N.
Krivorotov
, Y. T.
Cui
, R. A.
Buhrman
, and D. C.
Ralph
, Phys. Rev. B
78
, 024409
(2008
).11.
A. M.
Deac
, A.
Fukushima
, H.
Kubota
, H.
Maehara
, Y.
Suzuki
, S.
Yuasa
, Y.
Nagamine
, K.
Tsunekawa
, D. D.
Djayaprawira
, and N.
Watanabe
, Nat. Phys.
4
, 803
(2008
).12.
J. C.
Slonczewski
, J. Magn. Magn. Mater.
159
, L1
(1996
).13.
L.
Berger
, Phys. Rev. B
54
, 9353
(1996
).14.
W. H.
Rippard
, M. R.
Pufall
, S.
Kaka
, T. J.
Silva
, and S. E.
Russek
, Phys. Rev. B
70
, 100406
(R) (2004
).15.
R.
Fisher
, International Symposium Signals, Systems and Electronics
, 2007
(unpublished), pp. 103
–105
.16.
K.
Strohm
, H. -L.
Bloecher
, R.
Schneider
, and J.
Wenger
, European Radar Conference
, 2005
(unpublished), pp. 165
–168
.17.
A. N.
Slavin
and P.
Kabos
, IEEE Trans. Magn.
41
, 1264
(2005
).18.
F. B.
Mancoff
, N. D.
Rizzo
, B. N.
Engel
, and S.
Tehrani
, Appl. Phys. Lett.
88
, 112507
(2006
).19.
A.
Slavin
and V.
Tiberkevich
, Phys. Rev. Lett.
95
, 237201
(2005
).20.
J. C.
Slonczewski
, J. Magn. Magn. Mater.
195
, 261
(1999
).21.
M. A.
Hoefer
, M. J.
Ablowitz
, B.
Ilan
, M. R.
Pufall
, and T. J.
Silva
, Phys. Rev. Lett.
95
, 267206
(2005
).22.
G.
Gerhart
, E.
Bankowski
, G. A.
Melkov
, V. S.
Tiberkevich
, and A. N.
Slavin
, Phys. Rev. B
76
, 024437
(2007
).23.
G.
Consolo
, B.
Azzerboni
, L.
Lopez-Diaz
, G.
Gerhart
, E.
Bankowski
, V.
Tiberkevich
, and A. N.
Slavin
, Phys. Rev. B
78
, 014420
(2008
).24.
M.
Tsoi
, A.
Jansen
, J.
Bass
, W.
Chiang
, V.
Tsoi
, and P.
Wyder
, Nature (London)
406
, 46
(2000
).© 2009 American Institute of Physics.
2009
American Institute of Physics
You do not currently have access to this content.
