466
17 Magnetic Semiconductors
Table 17.1 Material properties of Eu chalcogenides. ‘FM’ (‘AF’) denotes ferromagnetic (antiferromagnetic) order. T C
(T N ) denotes the Curie (Néel) temperature. Data collected in [1525]
Material
E g (eV)
Magnetic order
T C , T N (K)
EuO
1.12
FM
69.3
EuS
1.65
FM
16.6
EuSe
1.8
AF
4.6
FM
2.8
EuTe
2.00
AF
9.6
Fig. 17.1 Heisenberg
nearest (J 1 , squares) and
next-nearest (J 2 , circles)
exchange parameters (in
units of J 1,2 /k B ) for the Eu
chalcogenides versus the
Eu–anion distance. Dashed
lines are guides to the eye.
Experimental data
from [1525]
Table 17.2 3d, 4d and 5d transition metals and their electron configurations. Note that Hf 72 has an incompletely filled
4f-shell with 4f 14
Sc 21
Ti 22
V 23
Cr 24
Mn 25
Fe 26
Co 27
Ni 28
Cu 29
Zn 30
3d
3d 2
3d 3
3d 4
3d 5
3d 6
3d 7
3d 8
3d 9
3d 10
4s 2
4s 2
4s 2
4s
4s 2
4s 2
4s 2
4s 2
4s
4s 2
Y 39
Zr 40
Nb 41
Mo 42
Tc 43
Ru 44
Rh 45
Pd 46
Ag 47
Cd 48
4d
4d 2
4d 3
4d 4
4d 5
4d 6
4d 7
4d 8
4d 9
4d 10
5s 2
5s 2
5s
5s
5s
5s
5s
–
5s
5s 2
La 57
Hf 72
Ta 73
W 74
Re 75
Os 76
Ir 77
Pt 78
Au 79
Hg 80
5d
5d 2
5d 3
5d 4
5d 5
5d 6
5d 7
5d 8
5d 9
5d 10
6s 2
6s 2
6s 2
6s 2
6s 2
6s 2
6s 2
6s
6s
6s 2
electrons are transferred from the anionic p states to the 5d states of the Eu
2+ cations, resulting in an
antiferromagnetic coupling.
17.3 Diluted Magnetic Semiconductors
In Table 17.2, the transition metals and their electron configurations are summarized. The 3d transition
metals are typically used for magnetic impurities in DMS due to their partially filled 3d shell. Due to
Hund’s rule, the spins on the 3d shell are filled in parallel for the first five electrons up to half filling (in
17 Magnetic Semiconductors
Table 17.1 Material properties of Eu chalcogenides. ‘FM’ (‘AF’) denotes ferromagnetic (antiferromagnetic) order. T C
(T N ) denotes the Curie (Néel) temperature. Data collected in [1525]
Material
E g (eV)
Magnetic order
T C , T N (K)
EuO
1.12
FM
69.3
EuS
1.65
FM
16.6
EuSe
1.8
AF
4.6
FM
2.8
EuTe
2.00
AF
9.6
Fig. 17.1 Heisenberg
nearest (J 1 , squares) and
next-nearest (J 2 , circles)
exchange parameters (in
units of J 1,2 /k B ) for the Eu
chalcogenides versus the
Eu–anion distance. Dashed
lines are guides to the eye.
Experimental data
from [1525]
Table 17.2 3d, 4d and 5d transition metals and their electron configurations. Note that Hf 72 has an incompletely filled
4f-shell with 4f 14
Sc 21
Ti 22
V 23
Cr 24
Mn 25
Fe 26
Co 27
Ni 28
Cu 29
Zn 30
3d
3d 2
3d 3
3d 4
3d 5
3d 6
3d 7
3d 8
3d 9
3d 10
4s 2
4s 2
4s 2
4s
4s 2
4s 2
4s 2
4s 2
4s
4s 2
Y 39
Zr 40
Nb 41
Mo 42
Tc 43
Ru 44
Rh 45
Pd 46
Ag 47
Cd 48
4d
4d 2
4d 3
4d 4
4d 5
4d 6
4d 7
4d 8
4d 9
4d 10
5s 2
5s 2
5s
5s
5s
5s
5s
–
5s
5s 2
La 57
Hf 72
Ta 73
W 74
Re 75
Os 76
Ir 77
Pt 78
Au 79
Hg 80
5d
5d 2
5d 3
5d 4
5d 5
5d 6
5d 7
5d 8
5d 9
5d 10
6s 2
6s 2
6s 2
6s 2
6s 2
6s 2
6s 2
6s
6s
6s 2
electrons are transferred from the anionic p states to the 5d states of the Eu
2+ cations, resulting in an
antiferromagnetic coupling.
17.3 Diluted Magnetic Semiconductors
In Table 17.2, the transition metals and their electron configurations are summarized. The 3d transition
metals are typically used for magnetic impurities in DMS due to their partially filled 3d shell. Due to
Hund’s rule, the spins on the 3d shell are filled in parallel for the first five electrons up to half filling (in