We herein report the achievement of exceptionally high coercivity (Hc) values: 9.92 and 5.86 kOe at 5 and 300 K, respectively, for Mn55Al43Cu2 flakes produced by surfactant-assisted milling process without employing any heat-treatment. The use of surfactants such as oleic acid and oleylamine during milling yielded high-aspect ratio flakes for the Mn-Al-Cu alloy. Structural studies confirmed the presence of τ- and β-phases as the major constituents in the Mn-Al-Cu flakes. The observed Hc enhancement is due to the increase in anisotropy field and structural defects, which is hypothesized to originate from the domain-wall pinning as a consequence of precipitation of fine Cu-particles present at the grain boundaries.

1.
A. J. J.
Koch
,
P.
Hokkeling
,
M. G. V. D.
Steeg
, and
K. J.
De Vos
,
J. Appl. Phys.
31
,
75S
(
1960
).
2.
J. H.
Park
,
Y. K.
Hong
,
S.
Bae
,
J. J.
Lee
,
J.
Jalli
,
G. S.
Abo
,
N.
Neveu
,
S. G.
Kim
,
C. J.
Choi
, and
J. G.
Lee
,
J. Appl. Phys.
107
,
09A731
(
2010
).
3.
Q.
Zeng
,
I.
Baker
, and
Z.-C.
Yan
,
J. Appl. Phys.
99
,
08E902
(
2006
).
4.
L.
Pareti
,
F.
Bolzoni
,
F.
Leccabue
, and
A.
Ermakov
,
J. Appl. Phys.
59
,
3824
(
1986
).
5.
Q.
Zeng
,
I.
Baker
,
J. B.
Cui
, and
Z. C.
Yan
,
J. Magn. Magn. Mater.
308
,
214
(
2007
).
6.
Z. W.
Liu
,
C.
Chen
,
Z. G.
Zheng
,
B. H.
Tan
, and
R. V.
Ramanujan
,
J. Mater. Sci.
47
,
2333
(
2012
).
7.
D. C.
Crew
,
P. G.
McCormick
, and
R.
Street
,
Scr. Metall. Mater.
32
,
315
(
1995
).
8.
P.
Saravanan
,
V. T. P.
Vinod
,
M.
Černík
,
D.
Chakravarty
,
P.
Ghosal
, and
S. V.
Kamat
,
Mater. Lett.
137
,
369
(
2014
).
9.
O.
Obi
,
L.
Burns
,
Y.
Chen
,
T.
Fitchorov
,
S.
Kim
,
K.
Hsu
,
D.
Heiman
,
L. H.
Lewis
, and
V. G.
Harris
,
J. Alloys Compd.
582
,
598
(
2014
).
10.
R.
Skomski
,
J. Appl. Phys.
81
,
5627
(
1997
).
11.
H.-W.
Zhang
,
Z.-G.
Sun
,
S.-Y.
Zhang
,
B.-S.
Han
, and
B.-G.
Shen
,
Phy. Rev. B
60
,
64
(
1999
).
12.
B. Z.
Cui
,
W. F.
Li
, and
G. C.
Hadjipanayis
,
Acta Mater.
59
,
563
(
2011
).
13.
B. Z.
Cui
,
L. Y.
Zheng
,
W. F.
Li
,
J. F.
Liu
, and
G. C.
Hadjipanayis
,
Acta Mater.
60
,
1721
(
2012
).
14.
H.
Okamoto
,
J. Phase Equilib.
18
,
398
(
1997
).
15.
P.
Kharel
,
R.
Skomski
,
R. D.
Kirby
, and
D. J.
Sellmyer
,
J. Appl. Phys.
107
,
09E303
(
2010
).
16.
P. C.
Kuo
,
Y. D.
Yao
,
J. H.
Huang
, and
C. H.
Chen
,
J. Magn. Magn. Mater.
115
,
183
(
1992
).
17.
N.
Singh
,
V.
Mudgil
,
K.
Anand
,
A. K.
Srivastava
,
R. K.
Kotnala
, and
A.
Dhar
,
J. Alloy Compd.
633
,
401
(
2015
).
18.
E.
Fazakas
,
L. K.
Varga
, and
F.
Mazaleyrat
,
J. Alloys Compd.
434–435
,
611
(
2007
).
19.
P.
Saravanan
,
R.
Gopalan
,
N. V.
Rama Rao
,
M.
Manivel Raja
, and
V.
Chandrasekaran
,
J. Phys. D: Appl. Phys.
40
,
5021
(
2007
).
20.
F.
Jiménez-Villacorta
,
J. L.
Marion
,
T.
Sepehrifar
,
M.
Daniil
,
M. A.
Willard
, and
L. H.
Lewis
,
App. Phys. Lett.
100
,
112408
(
2012
).
21.
G. F.
Korznikova
,
Solid State Phenom.
215
,
415
(
2014
).
22.
R.
Skomski
,
P.
Manchanda
,
P.
Kumar
,
B.
Balamurugan
,
A.
Kashyap
, and
D. J.
Sellmyer
,
IEEE Trans. Magn.
49
,
3215
(
2013
).
23.
Q.
Jin
,
J.-P.
Eom
,
S.-G.
Lim
,
W.-W.
Park
, and
B.-S.
You
,
Scr. Mater.
49
,
1129
(
2003
).
24.
H.
Kronmüller
and
D.
Goll
,
Scr. Mater.
47
,
545
(
2002
).
25.
T.
Schrefi
,
J.
Fidler
, and
H.
Kronmuller
,
Phys. Rev. B
49
,
6100
(
1994
).
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