On origin of room temperature ferromagnetism in wide gap semiconductors
The emerging field of semiconductor spintronics would be dramatically boosted if a semiconductor exhibiting room-temperature ferromagnetism could be found. Here, we discuss the recent stage of the research, paying particular attention to the understanding of observed room temperature ferromagnetism...
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nasplib_isofts_kiev_ua-123456789-1167652025-06-03T16:26:44Z On origin of room temperature ferromagnetism in wide gap semiconductors Korbecka, Anna Majewski, Jacek A. XVII Уральская международная зимняя школа по физике полупроводников The emerging field of semiconductor spintronics would be dramatically boosted if a semiconductor exhibiting room-temperature ferromagnetism could be found. Here, we discuss the recent stage of the research, paying particular attention to the understanding of observed room temperature ferromagnetism in wide band semiconductors, GaMnN and ZnMnO. Since the spinodal decomposition has been observed in these structures, we consider the possibilities to influence density fluctuations of the alloys to obtain ferromagnetic semiconductors with required functionalities. We contrast these compounds with (In,Mn)As and (Ga,Mn)As, where the ferromagnetism is well understood, albeit well below room temperature. This work was supported by the Polish Ministry of Science and High Education (project N202 026 32/0707) and partly by the EC project NANOSPIN (FP6-2002-IST-015728). 2009 Article On origin of room temperature ferromagnetism in wide gap semiconductors / Anna Korbecka, Jacek A. Majewski // Физика низких температур. — 2009. — Т. 35, № 1. — С. 70-74. — Бібліогр.: 45 назв. — англ. PACS: 75.50.Pp https://nasplib.isofts.kiev.ua/handle/123456789/116765 en Физика низких температур application/pdf Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України |
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XVII Уральская международная зимняя школа по физике полупроводников XVII Уральская международная зимняя школа по физике полупроводников |
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XVII Уральская международная зимняя школа по физике полупроводников XVII Уральская международная зимняя школа по физике полупроводников Korbecka, Anna Majewski, Jacek A. On origin of room temperature ferromagnetism in wide gap semiconductors Физика низких температур |
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The emerging field of semiconductor spintronics would be dramatically boosted if a semiconductor exhibiting room-temperature ferromagnetism could be found. Here, we discuss the recent stage of the research, paying particular attention to the understanding of observed room temperature ferromagnetism in wide band semiconductors, GaMnN and ZnMnO. Since the spinodal decomposition has been observed in these structures, we consider the possibilities to influence density fluctuations of the alloys to obtain ferromagnetic semiconductors with required functionalities. We contrast these compounds with (In,Mn)As and (Ga,Mn)As, where the ferromagnetism is well understood, albeit well below room temperature. |
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Korbecka, Anna Majewski, Jacek A. |
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On origin of room temperature ferromagnetism in wide gap semiconductors |
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On origin of room temperature ferromagnetism in wide gap semiconductors |
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On origin of room temperature ferromagnetism in wide gap semiconductors |
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On origin of room temperature ferromagnetism in wide gap semiconductors |
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On origin of room temperature ferromagnetism in wide gap semiconductors |
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on origin of room temperature ferromagnetism in wide gap semiconductors |
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Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України |
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On origin of room temperature ferromagnetism in wide gap semiconductors / Anna Korbecka, Jacek A. Majewski // Физика низких температур. — 2009. — Т. 35, № 1. — С. 70-74. — Бібліогр.: 45 назв. — англ. |
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Физика низких температур |
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AT korbeckaanna onoriginofroomtemperatureferromagnetisminwidegapsemiconductors AT majewskijaceka onoriginofroomtemperatureferromagnetisminwidegapsemiconductors |
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Fizika Nizkikh Temperatur, 2009, v. 35, No. 1, p. 70–74
On origin of room temperature ferromagnetism
in wide gap semiconductors
Anna Korbecka and Jacek A. Majewski
Institute of Theoretical Physics & Interdisciplinary Center for Modeling of Materials University of Warsaw,
ul. Hoza 69, 00-681 Warszawa, Poland
E-mail: Jacek.Majewski@fuw.edu.pl
Received August 13, 2008
The emerging field of semiconductor spintronics would be dramatically boosted if a semiconductor ex-
hibiting room-temperature ferromagnetism could be found. Here, we discuss the recent stage of the research,
paying particular attention to the understanding of observed room temperature ferromagnetism in wide band
semiconductors, GaMnN and ZnMnO. Since the spinodal decomposition has been observed in these struc-
tures, we consider the possibilities to influence density fluctuations of the alloys to obtain ferromagnetic
semiconductors with required functionalities. We contrast these compounds with (In,Mn)As and
(Ga,Mn)As, where the ferromagnetism is well understood, albeit well below room temperature.
PACS: 75.50.Pp Magnetic semiconductors.
Keywords: ferromagnetic semiconductors, diluted magnetic semiconductors, spinodal decomposition, wide
band gap semiconductors.
1. Introduction
The idea of a spin transistor [1] has given rise to
spintronics — a new emerging field of solid state physics
[2], where the central theme is the active manipulation of
spin degrees of freedom in solid-state, and/or molecular
systems [3], in addition to the degrees of freedom con-
nected to the electron charge. This offers new opportuni-
ties for novel devices that could combine standard elec-
tronics with the spin dependent effects that arise from the
interaction between spin of the carriers and the magnetic
properties of the material. It is hoped that the advantages
of these new devices would be , among others ,
nonvolatility, increased data processing speed, decreased
electric power consumption, and increased integration
densities. The vision of the spintronic systems and the
main directions of the future development have been for-
mulated in Ref. 2. The actual stage of research has been
already described in a series of reviews [4–6], mono-
graphs [7,8] and even a text book [9]. The spintronics in-
volves an intensive search for virtually all possible mate-
rials allowing the effective realization of spintronics
devices. In this search, the materials that combine semi-
conducting behavior with robust magnetism are of partic-
ular interest, since they could allow the fabrication of all
semiconductor devices.
2. Ferromagnetism in diluted magnetic semiconductors
2.1. Ferromagnetism in homogeneous DMSs
The first attempts to create material systems that could
be simultaneously semiconducting and magnetic range to
the late seventies [10], where the magnetic ions carrying
local magnetic moments have been introduced into well
known semiconductors. In this way, a new class of semi-
conductors has emerged so-called diluted magnetic semi-
conductors (DMSs). Later on, it has been shown that InAs
and GaAs heavily doped with Mn become ferromagnetic
with Curie temperatures of the order of 100 K [11]. It has
been also shown that Mn ion in these compounds acts si-
multaneously as the source of local moments and an accep-
tor. This implies that the originating ferromagnetism in this
type of DMSs could be mediated by free carriers, and is in
principle described by the so-called Zener’s kinetic ex-
change or indirect-exchange mechanism [12]. In the case
of (In,Mn)As or (Ga,Mn)As compounds, the coupling of
the local d-shell moments is mediated by p-band valence
electrons (i.e., holes). Based on Zener’s model, the theoret-
ical explanation of the ferromagnetism in (III,Mn)V com-
pounds with homogeneous distribution of substitutional
Mn ions in III–V cubic lattice has been provided by Dietl et
al. [13], however, it turned out that the details of the elec-
tronic structure of the valence band play an important role.
This mean field theory explains experimentally observed
© Anna Korbecka and Jacek A. Majewski, 2009
thermodynamic, micro-magnetic, transport, and optical
properties of DMS with delocalized holes. The problem of
ferromagnetism in (III,Mn)V DMSs has been extensively
studied both theoretically and experimentally (the sum-
mary of these studies can be found in an excellent review
of Jungwirth et al. [14]), and nowadays is considered to be
well understood. The Zener’s like mechanism can account
also for ferromagnetism in II–VI compounds doped with
transition metal ions [15]. In all these cases, the Curie tem-
perature TC , in agreement with theoretical predictions, is
well below the room temperature, with the highest ob-
served up to now value of TC being 173 K [16]. In the view
of spintronic applications, the ferromagnetic materials
with TC below room temperature are obviously not satis-
factory. Therefore, it is a strong research effort to find a
ferromagnetic semiconductor with TC above 300 K. It
seems that one of the direct ways to reach this goal would
be increase the Mn concentration. However, it turns out
that TC saturates with Mn concentration, as can be seen in
Fig. 1. The main reason of this behavior is the fact that at
higher concentrations Mn ions built in the interstitial posi-
tions of the III–V lattice. There they do not act as the ac-
ceptors (actually they act as double donors and each inter-
stitial Mn ion compensates two substitutional Mn
acceptors) and actually diminish the hole concentration
and as a consequence Curie temperature [14].
2.2. Ferromagnetism in wide band gap DMSs
However, the theoretical prediction of Dietl et al. [17]
(based on Zener ’s model of ferromagnetism) that
Mn-doped ZnO and GaN would be ferromagnetic at room
temperature provided the hole density would be large
enough, and a report of ferromagnetism in Co-doped TiO2
[18] gave the hope that Co- and Mn doped oxides and ni-
trides may indeed be useful for spintronics. In addition, the
theoretical calculations appeared [19] showing that ZnO
doped with several 3d transition metal ions such as V, Cr,
Fe, Co and Ni may exhibit ferromagnetic ordering. This
made the wide band gap materials very promising candi-
dates for spintronic materials and induced enormous re-
search effort devoted to these materials.
Many authors reported ferromagnetism above room
temperature in Co- and Mn-doped ZnO [20], whereas
other found magnetization only at low temperatures or
even no ferromagnetism at all [21], showing that the mag-
netic properties of these systems are best described by a
Curie–Weiss type behavior. In these systems, many other
magnetic phases have been reported indicating that the
growth conditions play decisive role in magnetic proper-
ties of these materials. These contradictory findings con-
cerning ferromagnetism in transition metal doped ZnO
led some authors to question the usefulness of these sys-
tems for spintronics [21]. These pessimistic conclusions
were supported also by theoretical calculations [22],
which excluded robust ferromagnetism in Mn and
Co-doped ZnO, at least unless the additional sources of
holes were provided, as predicted by Dietl et al. [17].
The studies of ferromagnetism in transition metal
doped GaN (and other nitrides) have been also not very
conclusive [23]. In 2001 successful growth of GaMnN
films showing room temperature ferromagnetism and
p-type conductivity has been reported [24]. The estima-
ted Curie temperature was 940 K at 5.7% of Mn, which is
highest among diluted magnetic semiconductors ever re-
ported. However, the physical origin of ferromagnetism
in this material remains still controversial. Other authors
also found room temperature ferromagnetism in GaMnN
layers of p-type [25], whereas some saw room tempera-
ture ferromagnetism and n-type layers [26] or did not ob-
serve ferromagnetism at all [27,28]. All these layers were
obtained in different growth processes, clearly indicating
the decisive role of growth conditions and rising question
about homogeneity of the layers. Also the question of the
role of external dopants has been addressed. In some
cases, additional p-type codoping (with Mg in the case of
GaN) should lead to enhancement of the carrier mediated
ferromagnetism [29], whereas theoretical studies conclu-
ded that extrinsic doping of p-type generating defects in
Mn doped GaN reduce the stability of the ferromagnetic
state [30]. Hence, according to them, p-type conditions
are not suitable for high temperature ferromagnetism in
Mn doped GaN [30].
These studies revealed that the physical mechanisms
of magnetism in the wide band gap DMSs (like GaN and
ZnO) can be very complicated in comparison to the situa-
tion in III–V compounds (exemplified by (Ga,Mn)As and
(In,Mn)As). The latter are systems with homogeneous
distribution of Mn ions, and their ferromagnetism can be
explained by mean field Zener’s type model. In contrary,
more accurate theoretical studies clearly demonstrated
that the Curie temperature in the homogeneous wide band
On origin of room temperature ferromagnetism in wide gap semiconductors
Fizika Nizkikh Temperatur, 2009, v. 35, No. 1 71
120
80
40
0
0.04 0.08
1024
1022
1020
1018
T
C
,
K
Mn concentration
H
o
le
d
en
si
ty
cm
,
–
3
Fig. 1. Dependence of the Curie temperature and the hole den-
sity in (Ga,Mn)As on the Mn concentration.
gap semiconductors GaMnN and ZnMnO can reach only
few K [31], in agreement with experimental data [32].
Therefore, at present it is commonly believed that the fer-
romagnetism in GaMnN and ZnMnO can originate from
the inhomogeneous character of these materials [33].
There is no universal theory of magnetism, and the mag-
netic order observed in various compounds can have quite
different origins that cause the coupling of localized mo-
ments in the solid. A useful starting point for developing a
model of magnetism is achieving a full understanding of
the electronic structure of a single Mn impurity in the host
lattice. Here, we discuss the energy level diagrams for Mn
impurity substituted on Ga site in GaAs and GaN lattices,
depicted in Figs. 2 and 3, proposed by many authors on
the basis of first-principles calculations (see e.g., the ref-
erence [34]). In both cases the hole is ascribed to the state
lying in the energy gap. However, in GaAs Mn 3d-levels
have lower energy than the anion dangling bond states
and the states in the gap are strongly hybridized, which
corresponds to the delocalized hole. In GaN, Mn 3d-lev-
els lie higher in energy than the anion dangling bond
states and, therefore, the states in the gap are weakly hy-
bridized and have mostly d-like character. In result, the
hole has the same d-like character and is strongly local-
ized on the Mn site. If many Mn ions are substituted into
the crystal, the levels will spread in the bands that con-
serve their character. One can expect narrow 3d-like im-
purity band in the energy gap of the GaN, whereas in
GaAs the delocalized hole states will overlap with the va-
lence band of the crystal. It is now clear that the physical
mechanism leading to the ferromagnetism in (Ga,Mn)As
(i.e., Zener’s like model) cannot work in the case of
(Ga,Mn)N, where narrow band magnetism could be rather
expected.
Further theoretical studies revealed further differences
between (Ga,Mn)As and (Ga,Mn)N. It turns out that the
hole mediated interactions between Mn ions are long
ranged in GaAs, but are short ranged in GaN [31]. There-
fore, usage of mean field theory to calculate Curie tem-
perature is completely not justified in the case of GaN.
This was the reason of false values of TC obtained in
earlies theoretical calculations for GaN [18]. Since the
ZnO resembles to some extend GaN, the physics of transi-
tion metal impurities in this material is similar to that of
GaN. The correct Monte Carlo calculations for (Ga,Mn)N
and (Zn,Mn)O homogeneous alloys give TC that is order
of magnitude lower than 300 K. Obviously, the room tem-
perature ferromagnetism observed in wide gap semicon-
ductors must originate in different physical phenomena.
2.3. Spinodal decomposition and ferromagnetism
in wide gap DMSs
In the moment it is believed that the spinodal decompo-
sition in the GaMnN alloy can lead to its ferromagnetic be-
havior [33]. It is well know that in the alloys exhibiting the
solubility gap in a certain concentration range the spinodal
decomposition occurs into regions with high and low con-
centration of constituents. In some cases it may lead to co-
herent nanoregions embedded in the majority component.
Such phenomenon is known to occur in GaInN alloy [35],
where In rich nanoscale regions are embedded in the In low
concentration regions. DMSs have particularly strong ten-
dency to form inhomogeneous alloys. According to the pi-
oneering ab initio work of van Schilfgaarde and Mryasov
72 Fizika Nizkikh Temperatur, 2009, v. 35, No. 1
Anna Korbecka and Jacek A. Majewski
Mn on Ga
Delocalized hole
t+
loc
e+
loc
e+
t+
t
hybrid
–
t+
hybrid
e–
t–
3d ion(d )n–1
t–
loc
e–
loc
t (p)+
VGa
3–
Anion
dangling
bonds
VBM
t (p)–
Fig. 2. The schematic energy level diagram for the hybridized
levels of Mn 3d-states and the neighboring anion dangling
bonds in GaAs. The 3d Mn ion levels are split by the crystal-
field and exchange interactions in the solid. In (Ga,Mn)As d
levels are energetically deeper than the dangling bond levels.
Mn on Ga
e+
t+
e–
t–
3d ion(d )n–1
VBM
t+
loc
e+
loc
t–
hybrid
t+
hybrid
t–
loc
e–
loc
t (p)+
Anion
dangling
bonds
t (p)–
Strongly
localized hole
VGa
3–
Fig. 3. The schematic energy level diagram for the hybridized
levels of Mn 3d-states and the neighboring anion dangling
bonds in GaN. The 3d Mn ion levels are split by the crystal-
field and exchange interactions in the solid. In the (Ga,Mn)N d
levels are energetically deeper than the dangling bond levels.
[36] and others [37] bringing two Ga-substitutional Mn
atoms together gives energy gain of 120 meV in GaAs and
300 meV in GaN, and in the case of Cr pair in GaN the
energy gain reaches even 350 meV [36].
The spinodal decomposition generally does not involve
a precipitation of another crystallographic phase. It is, the-
refore, not so easy detectable experimentally. Neverthe-
less, the electron transmission microscopy (TEM) experi-
ments [38,39] found coherent zinc-blende Mn-rich
(Mn,Ga)As nanocrystals in (Ga,Mn)As. It is believed that
these regions were responsible for the apparent Curie tem-
perature up to 360 K [39]. Furthermore, coherent hexago-
nal and diamond-type Mn-rich nanocrystals were detected
by spatially resolved X-ray diffraction in (Ga,Mn)N [40]
and by transmission electron microscopy in (Ge,Mn) [41],
respectively. The nanoregions with higher concentration of
magnetic moments, lead to ferromagnetic ordering of them
at temperatures usually higher than 300 K. Recent simula-
tions to large extend confirm this picture and are even able
to provide hints for effective epitaxial growth of ferromag-
netic compounds [37,42].
In order to obtain robust ferromagnetism, it may be
worthwhile to investigate the effect of co-doping of sam-
ples with other cations to induce additional charge carriers,
or samples with defect-induced carriers. It has been
demonstrated that in this way one can control the charge
state of the magnetic ions, and, therefore, their tendency to
cluster, just influencing the magnetic order in the system. It
has been demonstrated in the case of (Zn, Cr)Te alloy [43].
The ferromagnetism of (Zn, Cr)Te and the associated
magnetooptical and magnetotransport functionalities, are
dominated by the formation of Cr-rich (Zn,Cr)Te metallic
nanocrystals embedded in the Cr-poor (Zn, Cr)Te matrix.
Importantly, the formation of these nanocrystals can be
controlled by manipulating the charge state of the Cr ions
during the epitaxy. These findings provide insight into the
origin of the ferromagnetism in a broad range of semicon-
ductors and oxides, and indicate possible functionalities of
these composite systems. Furthermore, they demonstrate a
bottom-up method for self-organized nanostructure fabri-
cation that is applicable to any system in which charge
state of a constituent depends on the Fermi-level position
in the host semiconductor [43].
A new route toward high temperature ferromagnetism
in semiconductors is the idea of the so-called «sub-
surfactant epitaxy», i.e., optimal doping control of mag-
netic semiconductors in the process of epitaxial growth.
Subsurfactant epitaxy has been proposed first theoretically
[44]. The authors proposed the doping Mn into Ge in such
a way that takes advantage of the energetic and kinetic
characteristics of Mn at the growth front of Ge (100). It has
been confirmed experimentally later on [45]. The resulting
doping levels would normally be considered too low for
ferromagnetic ordering. However, GeMn structures grown
using this method exhibit the Curie temperature that ex-
ceeds room temperature by a comfortable margin [45].
This clearly demonstrates that deep understanding of
the self-organized growth can be utilized to obtain ferro-
magnetic materials of required functionalities.
3. Conclusions
The emerging field of semiconductor spintronics
would be dramatically boosted if a semiconductor exhib-
iting room-temperature ferromagnetism could be found.
Therefore, the discovery of ferromagnetism first in di-
luted magnetic semiconductors such as (In,Mn)As and
later in (Ga,Mn)As came as a landmark achievement. In
these materials, substitutional divalent Mn ions (with
concentration of several per cent) provide localized spins
and function as acceptor centers that provide holes which
mediate the ferromagnetic coupling between the parent
randomly distributed Mn spins. The ferromagnetism of
these systems is well understood and can be explained
within the p d� Zener’s exchange mechanism and the
Luttinger–Kohn kp theory of the valence band. This mean
field theory explains experimentally observed thermody-
namic, micromagnetic, transport, and optical properties
of DMS with delocalized holes. However, in spite of the
huge technological and experimental efforts, the highest
possible Curie temperature that was possible to accom-
plish up to now lies in the range of 173 K.
Stimulated partly by the theoretical predictions, search
for carrier-induced ferromagnetism in other types of
semiconductors containing Mn and other transition metal
ions begun and several observations of room temperature
ferromagnetism in wide-gap semiconductors have been
reported, e.g., in GaN:Mn, ZnO:Mn, and ZnO:Co. How-
ever, it is now known fairly well that the exchange inter-
actions in wide-gap II–VI and III–N (nitrides) DMSs is
dominated by Zener’s double exchange mechanism and is
short range. Therefore, the mean field theory applied to
(Ga,Mn)As is invalid in this case. Monte Carlo simula-
tions of Curie temperature give very low values of TC
(few Kelvin) and have been also confirmed in GaN:Mn
samples grown by molecular beam epitaxy. It became
clear that the room temperature ferromagnetism is impos-
sible in uniformly alloyed wide-gap compounds.
Therefore, a question arises, where the room tempera-
ture ferromagnetism in wide-gap semiconductors comes
from? The most serious candidate is spinodal decomposi-
tion in the moment, i.e., the appearance of regions with
higher concentration of one species of an alloy. Theoretical
works confirm the strong tendency of wide-gap DMSs to
form strongly nonrandom alloys. Since spinodal decompo-
sition does not usually involve a precipitation of another
crystallo-graphic phase, it is rather difficult to detect it ex-
perimentally. However, the Mn rich nanocrystals have
been observed in (Ge,Mn), (Ga,Mn)N, and (Ga,Mn)As.
On origin of room temperature ferromagnetism in wide gap semiconductors
Fizika Nizkikh Temperatur, 2009, v. 35, No. 1 73
One could expect that such spinodal decomposition is a ge-
neric property of a number of DMSs. Further, the suitable
control of growth process could lead to fabrication of fer-
romagnetic semiconductors at room temperature.
This work was supported by the Polish Ministry of
Science and High Education (project N202 026 32/0707)
a n d p a r t l y b y t h e E C p r o j e c t N A N O S P I N
(FP6-2002-IST-015728).
1. S. Data and B. Das, Appl. Phys. Lett. 56, 665 (1990).
2. S.A.Wolf, D.D. Awschalom, R.A. Buhrman, J.M. Daughton,
S. von Molnar, M.L. Roukes, A.Y. Chtchelkanova, and D.M.
Treger, Science 294, 1488 (2001).
3. D. Gatteschi, R. Sessoli, and J. Villain, Molecular Nano-
magnets, Oxford University Press (2006).
4. I. Zutic, J. Fabian, and S. Das Sarma, Rev. Mod. Phys. 76,
323 (2004).
5. C. Felser, G.H. Fecher, and B. Balke, Angew. Chem. Int.
Ed. 46, 668 (2007).
6. R. Hanson, L.P. Kouwenhoven, J.R. Petta, S. Tarucha, and
L.M.K. Vandersypen, Rev. Mod. Phys. 79, 1217 (2007).
7. Concepts in Spin Electronics, Sadamichi Maekawa (ed.)
Oxford University Press (2006).
8. Spintonic Materials and Technology, Y.B. Yu and S.M.
Thompson (eds.) Taylor & Francis, Boca Raton (2007).
9. Mathias Getzlaff, Fundamentals of Magnetism, Sprin-
ger–Verlag, Berlin (2008).
10. J.A. Gaj, J. Ginter, and R.R. Galazka, Phys. Status Solidi
B89, 655 (1978).
11. H. Ohno, H. Munekata, T. Penney, S. von Molnar, and L.L.
Chang, Phys. Rev. Lett. 68, 2664 (1992); H. Ohno, A. Shen,
F. Matsukura, A. Oiwa, A. Endo, S. Katsumoto, and Y. Iye,
Appl. Phys. Lett. 69, 363 (1996).
12. C. Zener, Phys. Rev. 81, 440 (1951a).
13. T. Dietl, H. Ohno, and F. Matsukura, Phys. Rev. B63, 195205
(2001).
14. T. Jungwirth, J. Sinova, J. Masek, J. Kucera, and A.H.
MacDonald, Rev. Mod. Phys. 78, 809 (2006).
15. T. Dietl, A. Haury, and Y. Merle d’Aubigne, Phys. Rev. B55,
R3347 (1997); T. Dietl, M. Sawicki, Le Van Khoi, J. Jaros-
zynski, P. Kossacki, J. Cibert, D. Ferrand, S. Tatarenko, and
A. Wasiela, Phys. Status Solidi B229, 665 (2002).
16. K.Y. Wang, R.P. Campion, K.W. Edmonds, M. Sawicki, T.
Dietl, C.T. Foxon, and B.L. Gallagher, Proc. ICPS 2004,
American Institute of Physic (2005).
17. T. Dietl, H. Ohno, F. Matsukura, J. Cibert. and D. Ferrand,
Science 287, 1019 (2000).
18. Y. Matsumoto, M. Murakami, T. Shono, T. Hasegawa, T.
Fukumura, M. Kawasaki, P. Ahmet, T. Chikyow, S.-Y. Ko-
shihara, and H. Koinuma, Science 291, 854 (2001).
19. K. Sato and H. Katayama–Yoshida, Jpn. J. Appl. Phys. 39,
L555 (2000).
20. see e.g., S.A. Chambers and R.F. C. Farrow, MRS Bull. 28,
729 (2003) and W. Prellier, A. Fouchet, and B. Mercey, J.
Phys.: Condens. Matter 15, R1583 (2003), and the refer-
ences therein.
21. C.N.R. Rao and F.L. Deepak, J. Mater. Chem. 15, 573 (2005).
22. N.A. Spaldin, Phys. Rev. B69, 125201 (2004).
23. C. Liu, F. Yun, and H. Morkoç, J. Mater. Science: Materi-
als in Electronics 16, 555 (2004).
24. S. Sonoda, S. Shimizu, T. Sasaki, Y. Yamamoto, and H.
Hori, J. Cryst. Growth. 237–239, 1358 (2002); H. Hori, S.
Sonoda, T. Sasaki, Y. Yamamoto, S. Shimizu, K. Suga,
and K. Kindo, Physica B324, 142 (2002).
25. K.H. Kim, K.J. Lee, D.J. Kim, H.J. Kim, Y. E. Ihm, D.
Djayaprawira, M. Takahashi, C.S. Kim, C.G. Kim, and S.H.
Yoo, Appl. Phys. Lett. 82, 1775 (2003).
26. S.J. Pearton, C.R. Abernathy, M.E. Overberg, G.T. Thaler,
D.P. Norton, N. Theodoropoulou, A.F. Hebard, Y.D. Park,
F. Ren, J. Kim, and L.A. Boatner, J. Appl. Phys. 93, 1
(2003).
27. M. Zajac, J. Gosk, M. Kaminska, A. Twardowski, T.
Szyszko, and S. Podsiadlo, Appl. Phys. Lett. 79, 2432 (2001).
28. Y.L. Soo, G. Kioseoglou, S. Kim, S. Huang, Y.H. Kao, S.
Kuwabara, S. Owa, T. Kondo, and H. Munekata, Appl.
Phys. Lett. 79, 3926 (2001).
29. K.H. Kim, K.J. Lee, D.J. Kim, H.J. Kim, Y.E. Ihm, C.G.
Kim, S.H. Yoo, and C.S. Kim, Appl. Phys. Lett. 82, 4755
(2003).
30. Priya Mahadevan and S. Mahalakshmi, Phys. Rev. B73,
153201 (2006).
31. K. Sato, P.H. Dederichs, and H. Katayama–Yoshida, J. Super-
conduc. 18, 33 (2005).
32. M.E. Overberg, C.R. Abernathy, S.J. Pearton, N.A. Theodo-
ropoulou, K.T. McCarthy, and A.F. Hebard, Appl. Phys.
Lett. 79, 1312 (2001).
33. T. Dietl, Physica E35, 293 (2006).
34. Priya Mahadevan and A. Zunger, Phys. Rev. B69, 115211
(2004).
35. M. Farhat and F. Bechstedt, Phys. Rev. B65, 075213 (2002).
36. M. van Schilfgaarde and O.N. Mryasov, Phys. Rev. B63,
233205 (2001).
37. K. Sato, H. Katayama-Yoshida, and P.H. Dederichs, Jpn.
J. Appl. Phys. 44, L948 (2005).
38. M. Moreno, A. Trampert, B. Jenichen, L. Daeweritz, and
K.H. Ploog, J. Appl. Phys. 92, 4672 (2002).
39. M. Yokoyama, H. Yamaguchi, T. Ogawa, and M. Tanaka,
J. Appl. Phys. 97, 317 (2005).
40. G. Martinez-Criado, A. Somogyi, S. Ramos, J. Campo, R.
Tucoulou, M. Salome, J. Susini, M. Hermann, M. Eickhoff,
and M. Stutzmann, Appl. Phys. Lett. 86, 131927 (2005).
41. M. Jamet, A. Barski, T. Devillers, V. Poydenot1, R. Dujardin,
P. Bayle–Guillmaud, J. Rotheman, E. Bellet–Amalric, A.
Marty, J. Cibert, R. Mattana, and S. Tatarenko, Nature Mat.
5, 653 (2006).
42. T. Fukushima, K. Sato, H. Katayama-Yoshida, and P.H.
Dederichs, Jpn. J. Appl. Phys. 45, L416 (2006).
43. S. Kuroda, N. Nishizawa, K. Takita, M. Mitome, Y. Ban-
do, K. Osuch, and T. Dietl, Nature Mat. 6, 440 (2007).
44. W.G. Zhu, H.H. Weitering, E.G. Wang, E. Kaxiras, and Z.
Zhang, Phys. Rev. Lett. 93, 126102 (2004).
45. C. Zeng, Z. Zhang, K van Benthem, M.F. Chrisholm, and
H.H. Weitering, Phys. Rev. Lett. 100, 066101 (2004).
74 Fizika Nizkikh Temperatur, 2009, v. 35, No. 1
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