Using THz emission spectroscopy, we detect spin-photo-currents from a ferrimagnetic amorphous alloy GdFeCo to an adjacent Pt capping layer. The currents are generated upon excitation of a GdFeCo/Pt heterostructure with femtosecond laser pulses. It is found that the polarization of the spin-polarized current is determined by magnetic sublattice sensitivity rather than the total magnetization, allowing for spin-polarized current generation when the net magnetization is zero.

1.
A.
Fert
, “
Nobel Lecture: Origin, development, and future of spintronics
,”
Rev. Mod. Phys.
80
,
1517
(
2008
).
2.
T.
Jungwirth
,
X.
Marti
,
P.
Wadley
, and
J.
Wunderlich
, “
Antiferromagnetic spintronics
,”
Nat. Nanotechnol.
11
,
231
(
2016
).
3.
T.
Kampfrath
,
M.
Battiato
,
P.
Maldonado
,
G.
Eilers
,
J.
Nötzold
,
S.
Mährlein
,
V.
Zbarsky
,
F.
Freimuth
,
Y.
Mokrousov
,
S.
Blügel
,
M.
Wolf
,
I.
Radu
,
P. M.
Oppeneer
, and
M.
Münzenberg
, “
Terahertz spin current pulses controlled by magnetic heterostructures
,”
Nat. Nanotechnol.
8
,
256
(
2013
).
4.
T. J.
Huisman
,
R. V.
Mikhaylovskiy
,
J. D.
Costa
,
F.
Freimuth
,
E.
Pa
,
J.
Ventura
,
P. P.
Freitas
,
S.
Blügel
,
Y.
Mokrousov
,
Th.
Rasing
, and
A. V.
Kimel
, “
Femtosecond control of electric currents in metallic ferromagnetic heterostructures
,”
Nat. Nanotechnol.
11
,
455
(
2016
).
5.
T.
Seifert
,
S.
Jaiswal
,
U.
Martens
,
J.
Hannegan
,
L.
Braun
,
P.
Maldonado
,
F.
Freimuth
,
A.
Kronenberg
,
J.
Henrizi
,
I.
Radu
,
E.
Beaurepaire
,
Y.
Mokrousov
,
P. M.
Oppeneer
,
M.
Jourdan
,
G.
Jakob
,
D.
Turchinovich
,
L. M.
Hayden
,
M.
Wolf
,
M.
Münzenberg
,
M.
Kläui
, and
T.
Kampfrath
, “
Efficient metallic spintronic emitters of ultrabroadband terahertz radiation
,”
Nat. Photonics
10
,
483
(
2016
).
6.
D.
Yang
,
J.
Liang
,
C.
Zhou
,
L.
Sun
,
R.
Zheng
,
S.
Luo
,
Y.
Wu
, and
J.
Qui
, “
Powerful and tunable THz emitters based on the Fe/Pt magnetic heterostructure
,”
Adv. Opt. Mater.
4
,
1944
1949
(
2016
).
7.
M.
Battiato
,
K.
Carva
, and
P. M.
Oppeneer
, “
Superdiffusive spin transport as a mechanism of ultrafast demagnetization
,”
Phys. Rev. Lett.
105
,
027203
(
2010
).
8.
G.
Malinowski
,
F.
Dalla Longa
,
J. H. H.
Rietjens
,
P. V.
Paluskar
,
R.
Huijink
,
H. J. M.
Swagten
, and
B.
Koopmans
, “
Control of speed and efficiency of ultrafast demagnetization by direct transfer of spin angular momentum
,”
Nat. Phys.
4
,
855
(
2008
).
9.
A.
Melnikov
,
I.
Razdolski
,
T. O.
Wehling
,
E. Th.
Papaioannou
,
V.
Roddatis
,
P.
Fumagalli
,
O.
Aktsipetrov
,
A. I.
Lichtenstein
, and
U.
Bovensiepen
, “
Ultrafast transport of laser-excited spin-polarized carriers in Au/Fe/Mgo(001)
,”
Phys. Rev. Lett.
107
,
076601
(
2011
).
10.
D.
Rudolf
,
C.
La-O-Vorakiat
,
M.
Battiato
,
R.
Adam
,
J. M.
Shaw
,
E.
Turgut
,
P.
Maldonado
,
S.
Mathias
,
P.
Grychtol
,
H. T.
Nembach
,
T. J.
Silva
,
M.
Aeschlimann
,
H. C.
Kapteyn
,
M. M.
Murnane
,
C. M.
Schneider
, and
P. M.
Oppeneer
, “
Ultrafast magnetization enhancement in metallic multilayers driven by superdiffusive spin current
,”
Nat. Commun.
3
,
1037
(
2012
).
11.
G.-M.
Choi
,
B.-C.
Min
,
K.-J.
Lee
, and
D. G.
Cahill
, “
Spin current generated by thermally driven ultrafast demagnetization
,”
Nat. Commun.
5
,
4334
(
2014
).
12.
G.
Gallot
and
Grischkowsky
, “
Electro-optic detection of terahertz radiation
,”
J. Opt. Soc. Am. B
16
,
1204
(
1999
).
13.
E.
Beaurepaire
,
G. M.
Turner
,
S. M.
Harrel
,
M. C.
Beard
,
J.-Y.
Bigot
, and
C. A.
Schmuttenmaer
, “
Coherent terahertz emission from ferromagnetic films excited by femtosecond laser pulses
,”
Appl. Phys. Lett.
84
,
3465
(
2004
).
14.
T. J.
Huisman
,
R. V.
Mikhaylovskiy
,
A.
Tsukamoto
,
T.
Rasing
, and
A. V.
Kimel
, “
Simultaneous measurements of terahertz emission and magneto-optical Kerr effect for resolving ultrafast laser-induced demagnetization dynamics
,”
Phys. Rev. B
92
,
104419
(
2015
).
15.
T. J.
Huisman
,
R. V.
Mikhaylovskiy
,
A.
Tsukamoto
,
L.
Ma
,
W. J.
Fan
,
S. M.
Zhou
,
Th.
Rasing
, and
A. V.
Kimel
, “
Sub 100-ps dynamics of the anomalous Hall effect at THz frequencies
,” e-print arXiv:1611.06251.
16.
C. D.
Stanciu
,
F.
Hansteen
,
A. V.
Kimel
,
A.
Kirilyuk
,
A.
Tsukamoto
,
A.
Itoh
, and
T.
Rasing
, “
All-optical magnetic recording with circularly polarized light
,”
Phys. Rev. Lett.
99
,
047601
(
2007
).
17.
K.
Vahaplar
,
A. M.
Kalashnikova
,
A. V.
Kimel
,
D.
Hinzke
,
U.
Nowak
,
R.
Chantrell
,
A.
Tsukamoto
,
A.
Itho
,
A.
Kirilyuk
, and
T.
Rasing
, “
Ultrafast path for optical magnetization reversal via a strongly nonequilibrium state
,”
Phys. Rev. Lett.
103
,
117201
(
2009
).
18.
I.
Radu
,
K.
Vahaplar
,
C.
Stamm
,
T.
Kachel
,
N.
Pontius
,
H. A.
Dürr
,
T. A.
Ostler
,
J.
Barker
,
R. F. L.
Evans
,
R. W.
Chantrell
,
A.
Tsukamoto
,
A.
Itoh
,
A.
Kirilyuk
,
Th.
Rasing
, and
A. V.
Kimel
, “
Transient ferromagnetic-like state mediating ultrafast reversal of antiferromagnetically coupled spins
,”
Nature
472
,
205
(
2011
).
19.
M.
Savoini
,
R.
Medapalli
,
B.
Koene
,
A. R.
Khorsand
,
L.
Le Guyader
,
L.
Duò
,
M.
Finazzi
,
A.
Tsukamoto
,
A.
Itoh
,
F.
Nolting
,
A.
Kirilyuk
,
A. V.
Kimel
, and
Th.
Rasing
, “
Highly efficient all-optical switching of magnetization in GdFeCo microstructures by interference-enhanced absorption of light
,”
Phys. Rev. B
86
,
140404
(
2012
).
20.
C. E.
Graves
,
A. H.
Reid
,
T.
Wang
,
B.
Wu
,
S.
de Jong
,
K.
Vahaplar
,
I.
Radu
,
D. P.
Bernstein
,
M.
Messerschmidt
,
L.
Müller
 et al, “
Nanoscale spin reversal by non-local angular momentum transfer following ultrafast laser excitation in ferrimagnetic GdFeCo
,”
Nat. Mater.
12
,
293
(
2013
).
You do not currently have access to this content.