Two-dimensional and van der Waals ferromagnets are ideal platform to study low-dimensional magnetism and proximity effects in van der Waals heterostructures. Their ultimate two-dimensional character also offers the opportunity to easily adjust their magnetic properties using strain or electric fields. Among 2D ferromagnets, the Cr 1 + xTe2 compounds with x = 0–1 are very promising because their magnetic properties depend on the amount of self-intercalated Cr atoms between pure CrTe2 layers and the Curie temperature ( T C) can reach room temperature for certain compositions. Here, we investigate the evolution of the composition as well as the structural and magnetic properties of thin Cr1.33Te2 (Cr2Te3) films epitaxially grown on graphene upon annealing. We observe a transition above 450 °C from the Cr1.33Te2 phase with perpendicular magnetic anisotropy and a T C of 180 K to a composition close to Cr 1.39Te2 with in-plane magnetic anisotropy and a T C of 240–250 K. This phase remains stable up to 650 °C above which a pure Cr film starts to form. This work demonstrates the complex interplay between intercalated Cr, lattice parameters, and magnetic properties in Cr 1 + xTe2 compounds.

1.
Q. H.
Wang
,
A.
Bedoya-Pinto
,
M.
Blei
,
A. H.
Dismukes
,
A.
Hamo
,
S.
Jenkins
,
M.
Koperski
,
Y.
Liu
,
Q.-C.
Sun
,
E. J.
Telford
,
H. H.
Kim
,
M.
Augustin
,
U.
Vool
,
J.-X.
Yin
,
L. H.
Li
,
A.
Falin
,
C. R.
Dean
,
F.
Casanova
,
R. F. L.
Evans
,
M.
Chshiev
,
A.
Mishchenko
,
C.
Petrovic
,
R.
He
,
L.
Zhao
,
A. W.
Tsen
,
B. D.
Gerardot
,
M.
Brotons-Gisbert
,
Z.
Guguchia
,
X.
Roy
,
S.
Tongay
,
Z.
Wang
,
M. Z.
Hasan
,
J.
Wrachtrup
,
A.
Yacoby
,
A.
Fert
,
S.
Parkin
,
K. S.
Novoselov
,
P.
Dai
,
L.
Balicas
, and
E. J. G.
Santos
, “
The magnetic genome of two-dimensional van der Waals materials
,”
ACS Nano
16
,
6960
7079
(
2022
).
2.
H.
Yang
,
S. O.
Valenzuela
,
M.
Chshiev
,
S.
Couet
,
B.
Dieny
,
B.
Dlubak
,
A.
Fert
,
K.
Garello
,
M.
Jamet
,
D.-E.
Jeong
,
K.
Lee
,
T.
Lee
,
M.-B.
Martin
,
G. S.
Kar
,
P.
Sénéor
,
H.-J.
Shin
, and
S.
Roche
, “
Two-dimensional materials prospects for non-volatile spintronic memories
,”
Nature
606
,
663
673
(
2022
).
3.
B.
Huang
,
G.
Clark
,
E.
Navarro-Moratalla
,
D. R.
Klein
,
R.
Cheng
,
K. L.
Seyler
,
D.
Zhong
,
E.
Schmidgall
,
M. A.
McGuire
,
D. H.
Cobden
,
W.
Yao
,
D.
Xiao
,
P.
Jarillo-Herrero
, and
X.
Xu
, “
Layer-dependent ferromagnetism in a van der Waals crystal down to the monolayer limit
,”
Nature
546
,
270
273
(
2017
).
4.
C.
Gong
,
L.
Li
,
Z.
Li
,
H.
Ji
,
A.
Stern
,
Y.
Xia
,
T.
Cao
,
W.
Bao
,
C.
Wang
,
Y.
Wang
,
Z. Q.
Qiu
,
R. J.
Cava
,
S. G.
Louie
,
J.
Xia
, and
X.
Zhang
, “
Discovery of intrinsic ferromagnetism in two-dimensional van der Waals crystals
,”
Nature
546
,
265
269
(
2017
).
5.
H.
Lv
,
A.
da Silva
,
A. I.
Figueroa
,
C.
Guillemard
,
I. F.
Aguirre
,
L.
Camosi
,
L.
Aballe
,
M.
Valvidares
,
S. O.
Valenzuela
,
J.
Schubert
,
M.
Schmidbauer
,
J.
Herfort
,
M.
Hanke
,
A.
Trampert
,
R.
Engel-Herbert
,
M.
Ramsteiner
, and
J. M. J.
Lopes
, “
Large-area synthesis of ferromagnetic Fe5−xGeTe2/graphene van der Waals heterostructures with curie temperature above room temperature
,”
Small
19
,
2302387
(
2023
).
6.
J. M. J.
Lopes
,
D.
Czubak
,
E.
Zallo
,
A. I.
Figueroa
,
C.
Guillemard
,
M.
Valvidares
,
J.
Rubio-Zuazo
,
J.
López-Sanchéz
,
S. O.
Valenzuela
,
M.
Hanke
, and
M.
Ramsteiner
, “
Large-area van der Waals epitaxy and magnetic characterization of Fe3GeTe2 films on graphene
,”
2D Mater.
8
,
041001
(
2021
).
7.
E.
Georgopoulou-Kotsaki
,
P.
Pappas
,
A.
Lintzeris
,
P.
Tsipas
,
S.
Fragkos
,
A.
Markou
,
C.
Felser
,
E.
Longo
,
M.
Fanciulli
,
R.
Mantovan
,
F.
Mahfouzi
,
N.
Kioussis
, and
A.
Dimoulas
, “
Significant enhancement of ferromagnetism above room temperature in epitaxial 2D van der Waals ferromagnet Fe5-δGeTe2/Bi2Te3 heterostructures
,”
Nanoscale
15
,
2223
2233
(
2023
).
8.
M.
Ribeiro
,
G.
Gentile
,
A.
Marty
,
D.
Dosenovic
,
H.
Okuno
,
C.
Vergnaud
,
J.-F.
Jacquot
,
D.
Jalabert
,
D.
Longo
,
P.
Ohresser
,
A.
Hallal
,
M.
Chshiev
,
O.
Boulle
,
F.
Bonell
, and
M.
Jamet
, “
Large-scale epitaxy of two-dimensional van der Waals room-temperature ferromagnet Fe5GeTe2
,”
npj 2D Mater. Appl.
6
,
10
(
2022
).
9.
E.
Vélez-Fort
,
A.
Hallal
,
R.
Sant
,
T.
Guillet
,
K.
Abdukayumov
,
A.
Marty
,
C.
Vergnaud
,
J.-F.
Jacquot
,
D.
Jalabert
,
J.
Fujii
,
I.
Vobornik
,
J.
Rault
,
N. B.
Brookes
,
D.
Longo
,
P.
Ohresser
,
A.
Ouerghi
,
J.-Y.
Veuillen
,
P.
Mallet
,
H.
Boukari
,
H.
Okuno
,
M.
Chshiev
,
F.
Bonell
, and
M.
Jamet
, “
Ferromagnetism and rashba spin–orbit coupling in the two-dimensional (V,Pt)Se2 alloy
,”
ACS Appl. Electron. Mater.
4
,
259
268
(
2022
).
10.
Z.
Li
,
S.
Liu
,
J.
Sun
,
J.
Zhu
,
Y.
Chen
,
Y.
Yang
,
L.
Ai
,
E.
Zhang
,
C.
Huang
,
P.
Leng
,
M.
Zhao
,
X.
Xie
,
Y.
Zhang
,
N. B.
Joseph
,
R.
Banerjee
,
A.
Narayan
,
J.
Zou
,
W.
Liu
,
X.
Xu
, and
F.
Xiu
, “
Low-pass filters based on van der Waals ferromagnets
,”
Nat. Electron.
6
,
273
280
(
2023
).
11.
Q.
Guillet
,
L.
Vojáček
,
D.
Dosenovic
,
F.
Ibrahim
,
H.
Boukari
,
J.
Li
,
F.
Choueikani
,
P.
Ohresser
,
A.
Ouerghi
,
F.
Mesple
,
V.
Renard
,
J.-F.
Jacquot
,
D.
Jalabert
,
H.
Okuno
,
M.
Chshiev
,
C.
Vergnaud
,
F.
Bonell
,
A.
Marty
, and
M.
Jamet
, “
Epitaxial van der Waals heterostructures of Cr2Te3 on two-dimensional materials
,”
Phys. Rev. Mater.
7
,
054005
(
2023
).
12.
D. C.
Freitas
,
R.
Weht
,
A.
Sulpice
,
G.
Remenyi
,
P.
Strobel
,
F.
Gay
,
J.
Marcus
, and
M.
Núñez-Regueiro
, “
Ferromagnetism in layered metastable 1T-CrTe2
,”
J. Phys.: Condens. Matter
27
,
176002
(
2015
).
13.
A.
Purbawati
,
J.
Coraux
,
J.
Vogel
,
A.
Hadj-Azzem
,
N.
Wu
,
N.
Bendiab
,
D.
Jegouso
,
J.
Renard
,
L.
Marty
,
V.
Bouchiat
,
A.
Sulpice
,
L.
Aballe
,
M.
Foerster
,
F.
Genuzio
,
A.
Locatelli
,
T. O.
Menteş
,
Z. V.
Han
,
X.
Sun
,
M.
Núñez-Regueiro
, and
N.
Rougemaille
, “
In-plane magnetic domains and Néel-like domain walls in thin flakes of the room temperature CrTe2 Van der Waals Ferromagnet
,”
ACS Appl. Mater. Interfaces
12
,
30702
30710
(
2020
).
14.
J.
Dijkstrat
,
H. H.
Weitering
,
C. F.
van Bruggen
,
C.
Haast
, and
R. A.
de Groot
, “
Band-structure calculations, and magnetic and transport properties of ferromagnetic chromium tellurides (CrTe, Cr3Te4, Cr,Te)
,”
J. Phys.: Condens. Matter
1
,
9141
(
1989
).
15.
K.
Lasek
,
P. M.
Coelho
,
P.
Gargiani
,
M.
Valvidares
,
K.
Mohseni
,
H. L.
Meyerheim
,
I.
Kostanovskiy
,
K.
Zberecki
, and
M.
Batzill
, “
Van der Waals epitaxy growth of 2D ferromagnetic Cr(1+δ)Te2 nanolayers with concentration-tunable magnetic anisotropy
,”
Appl. Phys. Rev.
9
,
011409
(
2022
).
16.
Y.
Fujisawa
,
M.
Pardo-Almanza
,
J.
Garland
,
K.
Yamagami
,
X.
Zhu
,
X.
Chen
,
K.
Araki
,
T.
Takeda
,
M.
Kobayashi
,
Y.
Takeda
,
C. H.
Hsu
,
F. C.
Chuang
,
R.
Laskowski
,
K. H.
Khoo
,
A.
Soumyanarayanan
, and
Y.
Okada
, “
Tailoring magnetism in self-intercalated Cr1+δTe2 epitaxial films
,”
Phys. Rev. Mater.
4
,
114001
(
2020
).
17.
Y.
Wang
,
S.
Kajihara
,
H.
Matsuoka
,
B. K.
Saika
,
K.
Yamagami
,
Y.
Takeda
,
H.
Wadati
,
K.
Ishizaka
,
Y.
Iwasa
, and
M.
Nakano
, “
Layer-number-independent two-dimensional ferromagnetism in Cr3Te4
,”
Nano Lett.
22
,
9964
9971
(
2022
).
18.
M. T.
Dau
,
M.
Gay
,
D.
Di Felice
,
C.
Vergnaud
,
A.
Marty
,
C.
Beigné
,
G.
Renaud
,
O.
Renault
,
P.
Mallet
,
T.
Le Quang
,
J.-Y.
Veuillen
,
L.
Huder
,
V. T.
Renard
,
C.
Chapelier
,
G.
Zamborlini
,
M.
Jugovac
,
V.
Feyer
,
Y. J.
Dappe
,
P.
Pochet
, and
M.
Jamet
, “
Beyond van der Waals interaction: The case of MoSe2 epitaxially grown on few-layer graphene
,”
ACS Nano
12
,
2319
2331
(
2018
).
19.
Y. J.
Dappe
,
Y.
Almadori
,
M. T.
Dau
,
C.
Vergnaud
,
M.
Jamet
,
C.
Paillet
,
T.
Journot
,
B.
Hyot
,
P.
Pochet
, and
B.
Grévin
, “
Charge transfers and charged defects in WSe2/graphene-SiC interfaces
,”
Nanotechnology
31
,
255709
(
2020
).
20.
K.
Abdukayumov
,
M.
Mičica
,
F.
Ibrahim
,
L.
Vojáček
,
C.
Vergnaud
,
A.
Marty
,
J.-Y.
Veuillen
,
P.
Mallet
,
I. G.
de Moraes
,
D.
Dosenovic
,
S.
Gambarelli
,
V.
Maurel
,
A.
Wright
,
J.
Tignon
,
J.
Mangeney
,
A.
Ouerghi
,
V.
Renard
,
F.
Mesple
,
J.
Li
,
F.
Bonell
,
H.
Okuno
,
M.
Chshiev
,
J.-M.
George
,
H.
Jaffrès
,
S.
Dhillon
, and
M.
Jamet
, “
Atomic-layer controlled transition from inverse Rashba–Edelstein effect to inverse spin hall effect in 2D PtSe2 probed by THz spintronic emission
,”
Adv. Mater.
36
,
2304243
(
2024
).
21.
B.
Kumar
,
M.
Baraket
,
M.
Paillet
,
J.-R.
Huntzinger
,
A.
Tiberj
,
A.
Jansen
,
L.
Vila
,
M.
Cubuku
,
C.
Vergnaud
,
M.
Jamet
,
G.
Lapertot
,
D.
Rouchon
,
A.-A.
Zahab
,
J.-L.
Sauvajol
,
L.
Dubois
,
F.
Lefloch
, and
F.
Duclairoir
, “
Growth protocols and characterization of epitaxial graphene on SiC elaborated in a graphite enclosure
,”
Physica E
75
,
7
14
(
2016
).
22.
P.
Ohresser
,
E.
Otero
,
F.
Choueikani
,
K.
Chen
,
S.
Stanescu
,
F.
Deschamps
,
T.
Moreno
,
F.
Polack
,
B.
Lagarde
,
J.-P.
Daguerre
,
F.
Marteau1
,
F.
Scheurer
,
L.
Joly
,
J.-P.
Kappler
,
B.
Muller
,
O.
Bunau
, and
P.
Sainctavit
, “
Deimos: A beamline dedicated to dichroism measurements in the 350–2500 eV energy range
,”
Rev. Sci. Instrum.
85
,
013106
(
2014
).
23.
B. T.
Thole
,
P.
Carra
,
F.
Sette
, and
G.
van der Laan
, “
X-ray circular dichroism as a probe of orbital magnetization
,”
Phys. Rev. Lett.
68
,
1943
1946
(
1992
).
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