Ultrafast magnetization switching at picosecond and sub-picosecond time scales has tremendous technological potential but still poses numerous questions regarding the underlying quantum mechanical phenomena, including the roles of and interactions between the electrons, spins, and phonons (lattice). At the nanometer-scale dimensions relevant for modern applications, these phenomena become increasingly more pronounced. Until now, helicity-independent all-optical switching (HI-AOS) has been largely limited to amorphous Gd-Fe-Co alloys, for which scaling was challenging due to their relatively low anisotropies. In this work, we demonstrate HI-AOS in amorphous GdCo and scale it to nanometer dimensions while still maintaining uniform out-of-plane magnetization. Single shot HI-AOS is demonstrated in these patterned samples down to a minimum optically detectable magnetic dot size of 200 nm. The ultrafast switching behavior was also confirmed using time-resolved magneto-optic Kerr effect measurements and found to settle to its opposite magnetization state at faster rates for smaller dot diameters, passing a threshold of 75% magnetization reversal within approximately 2 ps for a 200 nm dot compared to approximately 40 ps for a 15 μm pattern. The size dependence of the ultrafast switching is explained in terms of the electron-phonon and spin-lattice interactions.

1.
C.
Israel
,
N. D.
Mathur
, and
J. F.
Scott
,
Nat. Mater.
7
,
93
(
2008
).
2.
K.
Jabeur
,
G.
Di Pendina
,
F.
Bernard-Granger
, and
G.
Prenat
,
IEEE Electron Device Lett.
35
,
408
(
2014
).
3.
D. M.
Bromberg
,
M. T.
Moneck
,
V. M.
Sokalski
,
J.
Zhu
,
L.
Pileggi
, and
J. G.
Zhu
, in
International Electron Devices Meeting
(
2015
), pp.
33.1.1
33.1.4
.
4.
S.
Tehrani
,
J. M.
Slaughter
,
E.
Chen
,
M.
Durlam
,
J.
Shi
, and
M.
DeHerrera
,
IEEE Trans. Magn.
35
,
2814
(
1999
).
5.
W. J.
Gallagher
and
S. S. P.
Parkin
,
IBM J. Res. Dev.
50
,
5
(
2006
).
6.
B.
Koopmans
,
G.
Malinowski
,
F.
Dalla Longa
,
D.
Steiauf
,
M.
Fähnle
,
T.
Roth
,
M.
Cinchetti
, and
M.
Aeschlimann
,
Nat. Mater.
9
,
259
(
2010
).
7.
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,
Nat. Mater.
12
,
293
(
2013
).
8.
T. A.
Ostler
,
J.
Barker
,
R. F.
Evans
,
R. W.
Chantrell
,
U.
Atxitia
,
O.
Chubykalo-Fesenko
,
S.
El Moussaoui
,
L.
Le Guyader
,
E.
Mengotti
,
L. J.
Heyderman
 et al,
Nat. Commun.
3
,
666
(
2012
).
9.
E.
Beaurepaire
,
J.-C.
Merle
,
A.
Daunois
, and
J.-Y.
Bigot
,
Phys. Rev. Lett.
76
,
4250
(
1996
).
10.
C. D.
Stanciu
,
F.
Hansteen
,
A. V.
Kimel
,
A.
Kirilyuk
,
A.
Tsukamoto
,
A.
Itoh
, and
T.
Rasing
,
Phys. Rev. Lett.
99
,
047601
(
2007
).
11.
J.
Hohlfeld
,
C. D.
Stanciu
, and
A.
Rebei
,
Appl. Phys. Lett.
94
,
152504
(
2009
).
12.
M. S.
El Hadri
,
P.
Pirro
,
C.-H.
Lambert
,
S.
Petit-Watelot
,
Y.
Quessab
,
M.
Hehn
,
F.
Montaigne
,
G.
Malinowski
, and
S.
Mangin
,
Phys. Rev. B
94
,
064412
(
2016
).
13.
I.
Radu
,
K.
Vahaplar
,
C.
Stamm
,
T.
Kachel
,
N.
Pontius
,
H. A.
Dürr
,
T. A.
Ostler
,
J.
Barker
,
R. F.
Evans
,
R. W.
Chantrell
 et al,
Nature
472
,
205
(
2011
).
14.
S.
Wienholdt
,
D.
Hinzke
,
K.
Carva
,
P. M.
Oppeneer
, and
U.
Nowak
,
Phys. Rev. B
88
,
020406(R)
(
2013
).
15.
A. M.
Kalashnikova
and
V. I.
Kozub
,
Phys. Rev. B
93
,
054424
(
2016
).
16.
M.
Finazzi
,
M.
Savoini
,
A. R.
Khorsand
,
A.
Tsukamoto
,
A.
Itoh
,
L.
Duo
,
A.
Kirilyuk
, and
M.
Ezawa
,
Phys. Rev. Lett.
110
,
177205
(
2013
).
17.
T. M.
Liu
,
T.
Wang
,
A. H.
Reid
,
M.
Savoini
,
X.
Wu
,
B.
Koene
,
P.
Granitzka
,
C. E.
Graves
,
D. J.
Higley
,
Z.
Chen
 et al,
Nano Lett.
15
,
6862
(
2015
).
18.
L.
Le Guyader
,
S.
El Moussaoui
,
M.
Buzzi
,
R. V.
Chopdekar
,
L. J.
Heyderman
,
A.
Tsukamoto
,
A.
Itoh
,
A.
Kirilyuk
,
T.
Rasing
,
A. V.
Kimel
 et al,
Appl. Phys. Lett.
101
,
022410
(
2012
).
19.
N.
Honda
,
S.
Hinata
,
S.
Saito
,
N.
Honda
,
S.
Hinata
, and
S.
Saito
,
AIP Adv.
7
,
056518
(
2017
).
20.
A.
Mekonnen
,
A. R.
Khorsand
,
M.
Cormier
,
A. V.
Kimel
,
A.
Kirilyuk
,
A.
Hrabec
,
L.
Ranno
,
A.
Tsukamoto
,
A.
Itoh
, and
T.
Rasing
,
Phys. Rev. B
87
,
180406(R)
(
2013
).
21.
P.
Hansen
,
C.
Clausen
,
G.
Much
,
M.
Rosenkranz
, and
K.
Witter
,
J. Appl. Phys.
66
,
756
(
1989
).
22.
C. D.
Stanciu
,
A. V.
Kimel
,
F.
Hansteen
,
A.
Tsukamoto
,
A.
Itoh
,
A.
Kirilyuk
, and
T.
Rasing
,
Phys. Rev. B
73
,
220402(R)
(
2006
).
23.
S.
Alebrand
,
M.
Gottwald
,
M.
Hehn
,
D.
Steil
,
M.
Cinchetti
,
D.
Lacour
,
E. E.
Fullerton
,
M.
Aeschlimann
, and
S.
Mangin
,
Appl. Phys. Lett.
101
,
162408
(
2012
).
24.
R.
Moreno
,
T. A.
Ostler
,
R. W.
Chantrell
, and
O.
Chubykalo-Fesenko
,
Phys. Rev. B
96
,
014409
(
2017
).
25.
L. L.
Guyader
,
M.
Savoini
,
S. E.
Moussaoui
,
M.
Buzzi
,
A.
Tsukamoto
,
A.
Itoh
,
A.
Kirilyuk
,
T.
Rasing
,
a. V.
Kimel
, and
F.
Nolting
,
Nat. Commun.
6
,
5839
(
2015
).
26.
M.
Wietstruk
,
A.
Melnikov
,
C.
Stamm
,
T.
Kachel
,
N.
Pontius
,
M.
Sultan
,
C.
Gahl
,
M.
Weinelt
,
H. A.
Dürr
, and
U.
Bovensiepen
,
Phys. Rev. Lett.
106
,
127401
(
2011
).
27.
T. Q.
Qiu
and
C. L.
Tien
,
J. Heat Transfer
115
,
842
(
1993
).
28.
J. L.
Hostetler
,
A. N.
Smith
,
D. M.
Czajkowsky
, and
P. M.
Norris
,
Appl. Opt.
38
,
3614
(
1999
).
29.
P.
Corkum
,
F.
Brunel
,
N.
Sherman
, and
T.
Srinivasan-Rao
,
Phys. Rev. Lett.
61
,
2886
(
1988
).
30.
W.
Hubner
and
K. H.
Bennemann
,
Phys. Rev. B
53
,
3422
(
1996
).
31.
H. S.
Song
,
K. D.
Lee
,
C. Y.
You
,
B. G.
Park
, and
J. I.
Hong
,
J. Magn. Magn. Mater.
406
,
129
(
2016
).

Supplementary Material

You do not currently have access to this content.