A thermal-magnetic-electric valve with the free layer of exchange-spring type and inverse magnetoresistance is investigated. The structure has S-shaped current-voltage characteristics and can exhibit spontaneous oscillations when integrated with a conventional capacitor within a resonator circuit. The frequency of the oscillations can be controlled from essentially dc to the GHz range by the circuit capacitance.
REFERENCES
1.
G.
Binasch
, P.
Grünberg
, F.
Saurenbach
, and W.
Zinn
, Phys. Rev. B
39
, 4828
(1989
).2.
M. N.
Baibich
, J. M.
Broto
, A.
Fert
, F.
Nguyen Va Dau
, and F.
Petroff
, Phys. Rev. Lett.
61
, 2472
(1988
).3.
J. C.
Slonczewski
, J. Magn. Magn. Mater.
195
, L261
(1999
).4.
L.
Berger
, Phys. Rev. B
54
, 9353
(1996
). 5.
C.
Vouille
, A.
Barthélémy
, F.
Elokan Mpondo
, A.
Fert
, P. A.
Schroeder
, S. Y.
Hsu
, A.
Reilly
, and R.
Lolee
, Phys. Rev. B
60
, 6710
(1999
).6.
J. M.
George
, L. G.
Peraira
, A.
Barthélémy
, F.
Petroff
, L. B.
Steren
, J. L.
Duvail
, A.
Fert
, R.
Loloee
, P.
Holody
, and P. A.
Schroeder
, Phys. Rev. Lett.
72
, 408
(1994
).7.
J. P.
Renard
, P.
Bruno
, R.
Megy
, B.
Bbartenlian
, P.
Beauvillain
, C.
Chappert
, C.
Dupas
, E.
Kolb
, M.
Mulloy
, P.
Veillet
, and E.
Velu
, Phys. Rev. B
51
, 12821
(1995
).8.
S. Y.
Hsu
, A.
Barthélémy
, P.
Holody
, R.
Lolee
, P. A.
Schroeder
, and A.
Fert
, Phys. Rev. Lett.
78
, 2652
(1997
).9.
C.
Vouille
, A.
Fert
, A.
Barthélémy
, S. Y.
Hsu
, R.
Loloee
, and P. A.
Schroeder
, J. Appl. Phys.
81
, 4573
(1997
).10.
A. M.
Kadigrobov
, S.
Andersson
, D.
Radić
, R. I.
Shekhter
, M.
Jonson
, and V.
Korenivski
, J. Appl. Phys.
107
, 123706
(2010
).11.
J. E.
Davies
, O.
Hellwig
, E. E.
Fullerton
, J. S.
Jiang
, S. D.
Bader
, G. T.
Zimanyi
, and K.
Liu
, Appl. Phys. Lett.
86
, 262503
(2005
).12.
V.
Korenivski
and R. B.
van Dover
, J. Appl. Phys.
82
, 5247
(1997
).13.
V.
Korenivski
, J. Magn. Magn. Mater.
, 215-216,
800
(2000
).14.
V.
Korenivski
and D. C.
Worledge
, Appl. Phys. Lett.
86
, 252506
(2005
).15.
G.
Asti
, M.
Solzi
, M.
Ghidni
, and F. M.
Neri
, Phys. Rev. B
69
, 174401
(2004
)16.
For spin valves and MTJs, the T-dependence is typically less than a factor of 2 from 4 K to RT. Let us say from 30% at 4 K to 20% RT. So, 1% per 30 K or 0.03% per 1 K. We can say that “our own data” at near-above RT show similar small T-dependence.17It is important to note that, here and below, we consider variations of the temperature in the vicinity of the Curie temperature of the spacer, which is not in contact with the readout spin-valve, while the Curie temperature of layer 2 is .
17.
S.
Andersson
and V.
Korenivski
, IEEE Trans. Magn.
46
, 2140
(2010
).18.
Typical densities of critical currents needed for the torque effect in point-contact devices are 108 ÷ 109 A/cm2 for the current perpendicular to the layers (CPP). The record low torque critical current in a nanopillar device was reported in Ref. 19. (see Ref. 20). In our paper, we consider the case in which the torque effect is absent: that is, the torque critical current is higher than 108 A/cm2.
19.
Z.
Diao
, Z.
Li
, S.
Wang
, Y.
Ding
, A.
Panchula
, E.
Chen
, L.-C.
Wang
, and Y.
Huai
, J. Phys.: Condens. Matter
19
, 165209
(2007
).20.
D. C.
Ralph
and M. D.
Stiles
, J. Magn. Magn. Mater.
320
, 1190
(2008
). http://www.sciencedirect.com/science/article/pii/S030488530701011621.
A. A.
Andronov
, A. A.
Witt
, and S. E.
Khaikin
, Theory of Oscillations
(Pergamon
, Oxford
, 1966
).22.
I. L.
Prejbeanu
, W.
Kula
, K.
Ounadjela
, R. C.
Sousa
, O.
Redon
, B.
Dieny
, and J. P.
Nozieres
, IEEE Trans. Magn.
40
(4
), 2625
(2004
).© 2012 American Institute of Physics.
2012
American Institute of Physics
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