Room-temperature ferromagnetism has been observed in Fe-doped nanocrystals. The magnetism of the nanocrystals develops from diamagnetism to ferromagnetism and the paramagnetism on increasing nominal Fe doping concentration from . Transmission electron microscope (TEM) and high-resolution TEM data indicate that Fe-doped nanocrystals with the size of are organized to form a planarlike self-assembly via oriented aggregation. These assembled nanostructures effectively improve room-temperature ferromagnetism of the sample. The exchange interaction of ferric ions via an electron trapped in a bridging oxygen vacancy ( center) is employed to explain the ferromagnetism of Fe-doped nanocrystals.
REFERENCES
1.
H.
Schmid
, Ferroelectrics
162
, 665
(1994
).2.
T.
Lottermoser
, T.
Lonkai
, U.
Amann
, D.
Hohlwein
, J.
Ihringer
, and M.
Fiebig
, Nature (London)
430
, 541
(2004
).3.
M.
Fiebig
, J. Phys. D
38
, R123
(2005
).4.
J.
Wang
, J. B.
Neaton
, H.
Zheng
, V.
Nagarajan
, S. B.
Ogale
, B.
Liu
, D.
Viehland
, V.
Vaithyanathan
, D. G.
Schlom
, U. V.
Waghmare
, N. A.
Spaldin
, K. M.
Rabe
, M.
Wuttig
, and R.
Ramesh
, Science
299
, 1719
(2003
).5.
N. A.
Hill
, J. Phys. Chem. B
104
, 6694
(2000
).6.
W.
Eerenstein
, N. C.
Mathur
, and J. F.
Scott
, Nature (London)
442
, 75
(2006
).7.
N. A.
Spaldin
and M.
Fiebig
, Science
309
, 391
(2005
).8.
H.
Ohno
, Science
281
, 951
(1998
).9.
J. M. D.
Coey
, M.
Venkatesan
, and C. B.
Fitzgerald
, Nat. Mater.
4
, 173
(2005
).10.
H.
Meštric
, R. A.
Eichel
, T.
Kloss
, K. P.
Dinse
, S.
Lanbach
, P. C.
Schmidt
, K. A.
Schönau
, M.
Knapp
, and H.
Ehrenberg
, Phys. Rev. B
71
, 134109
(2005
).11.
G.
Xu
, Z.
Ren
, P.
Du
, W.
Weng
, G.
Shen
, and G.
Han
, Adv. Mater. (Weinheim, Ger.)
17
, 907
(2005
).12.
A. M.
Glazer
and S. A.
Mabud
, Acta Crystallogr.
B34
, 1065
(1978
).13.
R. L.
Penn
and J. F.
Banfield
, Science
281
, 969
(1998
).14.
J. M. D.
Coey
, A. P.
Douvalis
, C. B.
Fitzgerald
, and M.
Venkatesan
, Appl. Phys. Lett.
84
, 1332
(2004
).15.
A.
Punnoose
, J.
Hays
, A.
Thurber
, M. H.
Engelhard
, R. K.
Kukkadapu
, C.
Wang
, V.
Shutthanandan
, and S.
Thevuthasan
, Phys. Rev. B
72
, 1054402
(2005
).16.
J. D.
Bryan
, S. A.
Santangelo
, S. C.
Keveren
, and D. R.
Gamelin
, J. Am. Chem. Soc.
127
, 15568
(2005
).© 2007 American Institute of Physics.
2007
American Institute of Physics
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