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On the possibility of semiconducting or semimetallic properties in some aluminides, silicides and germanides of non-magnetic transition metals
PHYSICS LETTERS
Volume 83A, number 2
ON THE POSSIBILITY
OF SEMICONDUCTING
IN SOME ALUMINIDES, OF NON-MAGNETIC
11 May 1981
OR SEMIMETALLIC
PROPERTIES
SILICIDES AND GERMANIDES
TRANSITION
METALS
I.M. CHAPNIK Cavendish Laboratory,
Universiry of Cambridge, Cambridge CB3 OHE, England
Received 16 January 1981 Revised manuscript received 19 March 1981
Deviations of atomic volume from additivity are determined for transition metal germanides, silicides, and aluminides. On the basis of the interrelation between the atomic volume deviations and the occurrence of semiconducting properties the possibility of semiconducting properties in some compounds is indicated.
It was shown recently [l-3] , that there exists an interrelation between the occurrence of semiconducting (and probably semimetallic) properties and the deviation of the atomic volume of a compound from additivity. This interrelation has indicated that in an agreement with the theoretical considerations [4] the interatomic distances in semiconductors are larger than that in metals. The aim of the present note is to determine which of the known transition metal germanides, silicides and aluminides could possess semimetallic or semiconducting properties and therefore to be considered as possible thermo-electric materials [5]. The percentage deviation of the atomic volume (V) from the sum of its components (En) is given by 22-V ---xloo=u~,
K=mtn 2n
V
whereAV=EQ -V,cr=lOO(mtn)/2n;mandnare the numbers of transition metal and of Ge or Si atoms in the compound, respectively. The coefficient (m t n)/ 2n provides the normalization to the case of equiatomic compound, since the contraction is apparently mainly due to the presence of Ge or Si, having as a semiconducting element an anomalously large atomic volume. For the aluminides the more simple formula K = 100 X AV/V is adopted. The crystallographic data were taken mainly from 0 03 l-9 163/81 /OOOO-0000/$02.50
0 North-Holland
the same sources as in the previous notes [ l-3,6 J . Calculated data of K and available data [7] of the superconducting transition temperatures (T,) are presented in tables 1,2 and 3 (known ferro- and antiferromagne tics are marked with an asterisk). The negative deviations from the additivity for aluminides and the negative or small positive deviations for germanides and silicides may be caused by the presence of atomic magnetic moments [3,8], by creation of closed electron subshells in the atomic cores outside the inert gas shells [9], or by .the possession of semimetallic or semiconducting properties [l-3]. Therefore some of the following aluminides, CrAl, , Cr+13,
Ud3,
UJQ,
U42,
ThN
n3A2mA2,
VAI,,,
CrAl4 (table 1);silicides Np3Si2, y -USi,, USi, U3Si2, U3Si, U3Si5 (table 2); germanides U,Ge,, ThGe, UGe,, ThGe, (table 3) probably could be semimetals or semiconductors. Although the compounds Th3Al2 and VAl,u (in samples comprising second phases) have been reported as being superconductors 171, the latter property, however, may be caused by the thin layers of the second phase precipitated on the grain boundaries [lo-121. On the other hand, the alloys Cr,Al, ReSi, and CrSi2, reported as being semiconductors (see ref. [3]), but displaying no negative or small positive deviation, are apparently metals. But the low conductivity observed is probably due to the presence of thin layers of Publishing Company
77
-13
Cu2Mg
NpA2
< 0.4
2.6
1.6
-5
-5
-5 -5 -3 -2
CrB AlB,
u3A12
cubic
ThA12
Tha Afz
VAIIO
1.6 < 1.3
0
CsCl hexag.
WA112
CsCl
&W
Real2
Nb3Al
WMl2
TC%2
M3M
monocl.
v7Abs
V4A123
+1
18.1
3.1
< 1.1
0
+1
-
0.9
0 0
0
3.3
-1
cu_Mn
Re&fs Ts, Al
-1
cubic
W&2
0.2
< 1.0 -
-2 -1
Ni3 Sn
wa12
Moh2
-
mA3
n2A17
CrAl4 Th,Al
ThAl
0.1
< 1.1 -
-8 -7
Cu2Mg
u‘4l2
-
CrsAk
< 2.0
UAl4
monocl. CuA12 orthor.
Cr3 Al*
< 0.1
-10 -8
UN3
-10
UAb Cu3Au orthor.
NPALI
TcAl4
MoAl
MoAls
WALs
Mo3Als
NbA13 Tc2 Al
TaAls
VAI,
Tal7Ml2
V3A
MosAl
Cr4a9
Cr2Al*
Tas Al Nb,Al
V&l8 MoA14
WAl,
TC2A13
ReAl4
V3M
< 4.0 -
-12
-11
monocl.
ReAb
TcAle
Comp.
CusAu
< 1.5 _
_
T, (K)
NPA~ *
AV
Cr2%3
*
-14
monocl.
CrAls
____~..~
loo, ____...__~~_
Struct.
+3
WA15 C&I monocl.
hexag.
MoSis monocl.
TiAls
TiA13
TiA13
P-W a-Mn
P-W
o-phase MoSi2 cubic
o-phase
@USi, ThSi ThsSi2
_ _
.I
Lu-USi
_
-
Us!& NpSi, U3Si
_
-,. -
_ ^ -
1.1 _
_
_
_
0.64 _
< 1.2
< 0.4
0.58 11.1 _
< 1.0 0.75 _ _
7
TasSi,
TasSis
Ta2 Si
_
Nbs Si3 NbSi,
NbsSi3
ThsSis
NbsSis TcsSi
Tas Si
p-ThSi, Nba Si
USia ol-ThSi2
U3 Si
_ _
U3Si2
NpsSia y-USi, USi
Comp.
< 2.5 -
1.85
_
6)
Tc
+9 +11
+8
+8
+8
+7
+7
+7
+5 +7
+5
+4 +4
+4
+3 +3
+3
cubic WA14
+3
+3
+2
+2
+2
+1 +2
+1
monocl.
rhomb .
CSCI
trigon.
CsCl tricl.
MnAls
MnAle
Struct.
-3
tetrag.
CrsSi,
Mns Si3
CuAl,
CrSi2
CrsSis
WsSi3
AlB2
Mns Si3 cubic
TisP
P-W
MB2
Cu3Au tetrag.
U3Si2
FeB
dB2
ThSi2 tetrag. cu-ThSi2
MB2
+26
+25
+25
+24
+23
+23
+23
+22
+15 +22 +22
+15
+14
+10 +11 +14
+9 +9
+8
+4 t7
0
-4
FeB Cus Au
-7
-12
Us Si2 cubic
Struct.
WsSi Tas Si3
_
< 1.2 < 0.1 _
< 1.02 _
TcsSi3
_
WsSi3
Tc4Si
CrsSi
ReSi,
V3 Si
CrSi,
CrsSi3
ResSi,
VSi2
V5Si3
VsSi3
CrSi
MosSi,
WSi, WsSi3
19.0 _
2.41
3.16
< 1.3
< 0.1
V&s
ReSi MosSi
_ _ < 0.35 _ _
MosSi MoSi,
_
CrsSi3 TcSi
TaSi2
Comp.
< 0.1
_ _
(K)
Tc
Mns Si3
P-W CsCl
P-W MoSi2
CrSi,
WsSi3
WsSi3
WsSi3
Mns Si3 CrSi2
WsSi3
W5Si3 FeSi
P-W WsSi3 NbeSu, MoSi, tetrag.
P-W
tetrag. FeSi
Mns Si3
Mns Si3 FeSi
CrSi2
StNCt.
V
+38
t37
+34
t34
+33 +34
t30
t30
+30
+30
t30
t30
+29 t29
+29
t29
t28 +29 +29
t28 t28
+28
+27
+26 i-27 +27
(J c
Silicides of transition metals with 5.6 and 7 outer electrons and thorium silicides.
Aluminides of transition metals with 5,6 and 7 outer electrons and thorium aluminides.
Comp.
Table 2
Table 1
1.4
< 0.02 _ _
< 1.15
16.8
< 1.2
-
_
< 1.2 _
< 0.35 _
< 1.2
-
< 1.2 _
_ _
_
< 1.2 _
-
< 1.2 _
11 May 1981
PHYSICS LRl-TERS
Volume 83A, number 2 Table 3 Germanides of transition metals. Comp.
U.&e3
MnsSia
ThGe
NaCl
0
UGe,
ZrSia
+5
ThGea
ZrSia
+6
ThaGe
CuAla
m3Ge2
Th3
-9
_ -
CrB orthor.
+12
-
+12
-
Cu3Au trigon. cubic
+13
d-GdSia
+17
0.87 1.49
+17
0.4
Ir4Ges Rh,,Geas
MnP tetrag. tetrag.
LaGea TiGe
a-SiaTh orthor.
HfGea
ZrSia
NbsGea Rh&% PdGe
MnsSia tetrag. MnP
IrGe TiaGe
MtlP Ni3P Ti3P orthor.
+20 +20
P-W MnP
+21 +21
ZrGea
ZrSia
+21
< 0.35
Hf3Ge
Ti3P
+21
< 1.8 1.3 -
IriGe7 LaCei PtGe
ZraGe OsaGea Nb3Ge RhGe
ZrSia ScGea Crr r Gers* tetrag.
+13 +15
< 0.35 -
< 1.2 -
+24 ~24
< 1.15
CrB CrB
+24
-
Fe2P
+25
< 1.2 -
ZraGe
hexag.
+25
< 1.8
Hf2Ge
CuAla
+25
< 0.05
Ws Sia
+26
CrSia Ua Si2
+26 +26
< 1.02 < 1.2 -
CrB
< 0.35 < 0.35
HfaGe, ScGe PdarGea
ptaa21
Zr5Q3
MnsSia
+26 +26 +26
MnsSia
+27
< 1.8
MoSi2 monocl.
+27 +27
-
+17
-
Hf&a p-MoGe2
+17
-
Pt3Ge
+18
2.24 _
RuGe
FeSi
+27
< 1.2 -
Scs Gea TieGes
Mns Sia orthor.
+27
-
+27 +27 +27 +27
< 1.2
+28 +28
-
+28
-
+18 +19 +19 +19 +19
+20 +21
+21 +22
2.2 -
CrrrGe8 CrGe*
CrsSia orthor. FeSi
Me-3
W&a
CrriQ3
< 0.35 4.7 < 1.7
Ta&a
< 1.8 -
VsGea
23.2 0.96
+22 +22
< 0.33
V17&31
monocl. tetrag.
MoGea
PbCla
+22
< 1.2
RU2 G3
orthor.
+22
NbGe2
CrSi2
+23
OsGea
+24
Nb&a TaGea
LaGe
--
+24
Pt2Ge
< 1.5 -
G)
TiSi2
< 0.1
+12
T,
MnsSia hexag.
< 0.07
+11
AV V
y&e3
+9
MnsSia
a-
TiGe2
+11
CaCls
UQ3
_ _.------
Sia
J-a@3
I&e4
stnlct.
____
NbroGe, YGe ZrGe
PtCea Pta Ge3
Comp.
2.1
oxides A1203 and Si02 on the grain or on the twin (if the crystal is twinned) boundaries [3].
vllGe8
WsSia Mns Si2 hexag.
TasGea Tis Gea
MnsSia MnsSia
+29 +29
PdzsGea
trigon. ThSi2 Fe2P
+29 +29
P-W orthor.
+31
%a3 Y&3
ya2
Pd,Ge Mo3Ge
3.0
+28
+30
< 1.2 3.8 < 0.35 1.5 2.12
W&a
+31 +32
-
m2G
PbC12
+33
-
v3Ge
P-w
+37
CraGe
P-W
+38
6.1 < 1.2 --.--
References [l] I.M. Chapnik, Philos. Mag. B37 (1978) 397.
79
Volume 83A, number 2 [2] [3] [4] [5]
PHYSICS LETTERS
I.M. Chap&, J. Mater. Sci. 12 (1977) 422. I.M.Chapnik, J. Mater. Sci. 15 (1980) 3175. N.F. Mott, Philos. Mag. 6 (1961) 287. D. Tuomi, Proc. 14th Intersociety energy conversion engineering Conf. (Boston, USA, August 1979) Part II (IEEE, New York 1979). [6] I.M. Chapnik, Phys. Stat. Sol. (a) (1980) K193. [7] B.W. Roberts, J. Phys. Chem. Ref. Data 5 (1976) 581.
80
11 May 1981
[8] I.M. Chapnik, Philos. Mag. 32 (1975) 673. [9] I.M. Chap&, J. Mater. Sci. 14 (1979) 2022. [lo] J.P. Charlesworth, Phys. Lett. 21 (1966) 501. [ 111 G. Arrenius, R. Fitzgerald, D. Hamilton, B.A. Holm and B.T. Matthias, J. Appl. Phys. 35 (1964) 3487. [ 121 T. Claeson and J. Ivarsson, J. Appl. Phys. 48 (1977) 3998.
Volume 83A, number 2
ON THE POSSIBILITY
OF SEMICONDUCTING
IN SOME ALUMINIDES, OF NON-MAGNETIC
11 May 1981
OR SEMIMETALLIC
PROPERTIES
SILICIDES AND GERMANIDES
TRANSITION
METALS
I.M. CHAPNIK Cavendish Laboratory,
Universiry of Cambridge, Cambridge CB3 OHE, England
Received 16 January 1981 Revised manuscript received 19 March 1981
Deviations of atomic volume from additivity are determined for transition metal germanides, silicides, and aluminides. On the basis of the interrelation between the atomic volume deviations and the occurrence of semiconducting properties the possibility of semiconducting properties in some compounds is indicated.
It was shown recently [l-3] , that there exists an interrelation between the occurrence of semiconducting (and probably semimetallic) properties and the deviation of the atomic volume of a compound from additivity. This interrelation has indicated that in an agreement with the theoretical considerations [4] the interatomic distances in semiconductors are larger than that in metals. The aim of the present note is to determine which of the known transition metal germanides, silicides and aluminides could possess semimetallic or semiconducting properties and therefore to be considered as possible thermo-electric materials [5]. The percentage deviation of the atomic volume (V) from the sum of its components (En) is given by 22-V ---xloo=u~,
K=mtn 2n
V
whereAV=EQ -V,cr=lOO(mtn)/2n;mandnare the numbers of transition metal and of Ge or Si atoms in the compound, respectively. The coefficient (m t n)/ 2n provides the normalization to the case of equiatomic compound, since the contraction is apparently mainly due to the presence of Ge or Si, having as a semiconducting element an anomalously large atomic volume. For the aluminides the more simple formula K = 100 X AV/V is adopted. The crystallographic data were taken mainly from 0 03 l-9 163/81 /OOOO-0000/$02.50
0 North-Holland
the same sources as in the previous notes [ l-3,6 J . Calculated data of K and available data [7] of the superconducting transition temperatures (T,) are presented in tables 1,2 and 3 (known ferro- and antiferromagne tics are marked with an asterisk). The negative deviations from the additivity for aluminides and the negative or small positive deviations for germanides and silicides may be caused by the presence of atomic magnetic moments [3,8], by creation of closed electron subshells in the atomic cores outside the inert gas shells [9], or by .the possession of semimetallic or semiconducting properties [l-3]. Therefore some of the following aluminides, CrAl, , Cr+13,
Ud3,
UJQ,
U42,
ThN
n3A2mA2,
VAI,,,
CrAl4 (table 1);silicides Np3Si2, y -USi,, USi, U3Si2, U3Si, U3Si5 (table 2); germanides U,Ge,, ThGe, UGe,, ThGe, (table 3) probably could be semimetals or semiconductors. Although the compounds Th3Al2 and VAl,u (in samples comprising second phases) have been reported as being superconductors 171, the latter property, however, may be caused by the thin layers of the second phase precipitated on the grain boundaries [lo-121. On the other hand, the alloys Cr,Al, ReSi, and CrSi2, reported as being semiconductors (see ref. [3]), but displaying no negative or small positive deviation, are apparently metals. But the low conductivity observed is probably due to the presence of thin layers of Publishing Company
77
-13
Cu2Mg
NpA2
< 0.4
2.6
1.6
-5
-5
-5 -5 -3 -2
CrB AlB,
u3A12
cubic
ThA12
Tha Afz
VAIIO
1.6 < 1.3
0
CsCl hexag.
WA112
CsCl
&W
Real2
Nb3Al
WMl2
TC%2
M3M
monocl.
v7Abs
V4A123
+1
18.1
3.1
< 1.1
0
+1
-
0.9
0 0
0
3.3
-1
cu_Mn
Re&fs Ts, Al
-1
cubic
W&2
0.2
< 1.0 -
-2 -1
Ni3 Sn
wa12
Moh2
-
mA3
n2A17
CrAl4 Th,Al
ThAl
0.1
< 1.1 -
-8 -7
Cu2Mg
u‘4l2
-
CrsAk
< 2.0
UAl4
monocl. CuA12 orthor.
Cr3 Al*
< 0.1
-10 -8
UN3
-10
UAb Cu3Au orthor.
NPALI
TcAl4
MoAl
MoAls
WALs
Mo3Als
NbA13 Tc2 Al
TaAls
VAI,
Tal7Ml2
V3A
MosAl
Cr4a9
Cr2Al*
Tas Al Nb,Al
V&l8 MoA14
WAl,
TC2A13
ReAl4
V3M
< 4.0 -
-12
-11
monocl.
ReAb
TcAle
Comp.
CusAu
< 1.5 _
_
T, (K)
NPA~ *
AV
Cr2%3
*
-14
monocl.
CrAls
____~..~
loo, ____...__~~_
Struct.
+3
WA15 C&I monocl.
hexag.
MoSis monocl.
TiAls
TiA13
TiA13
P-W a-Mn
P-W
o-phase MoSi2 cubic
o-phase
@USi, ThSi ThsSi2
_ _
.I
Lu-USi
_
-
Us!& NpSi, U3Si
_
-,. -
_ ^ -
1.1 _
_
_
_
0.64 _
< 1.2
< 0.4
0.58 11.1 _
< 1.0 0.75 _ _
7
TasSi,
TasSis
Ta2 Si
_
Nbs Si3 NbSi,
NbsSi3
ThsSis
NbsSis TcsSi
Tas Si
p-ThSi, Nba Si
USia ol-ThSi2
U3 Si
_ _
U3Si2
NpsSia y-USi, USi
Comp.
< 2.5 -
1.85
_
6)
Tc
+9 +11
+8
+8
+8
+7
+7
+7
+5 +7
+5
+4 +4
+4
+3 +3
+3
cubic WA14
+3
+3
+2
+2
+2
+1 +2
+1
monocl.
rhomb .
CSCI
trigon.
CsCl tricl.
MnAls
MnAle
Struct.
-3
tetrag.
CrsSi,
Mns Si3
CuAl,
CrSi2
CrsSis
WsSi3
AlB2
Mns Si3 cubic
TisP
P-W
MB2
Cu3Au tetrag.
U3Si2
FeB
dB2
ThSi2 tetrag. cu-ThSi2
MB2
+26
+25
+25
+24
+23
+23
+23
+22
+15 +22 +22
+15
+14
+10 +11 +14
+9 +9
+8
+4 t7
0
-4
FeB Cus Au
-7
-12
Us Si2 cubic
Struct.
WsSi Tas Si3
_
< 1.2 < 0.1 _
< 1.02 _
TcsSi3
_
WsSi3
Tc4Si
CrsSi
ReSi,
V3 Si
CrSi,
CrsSi3
ResSi,
VSi2
V5Si3
VsSi3
CrSi
MosSi,
WSi, WsSi3
19.0 _
2.41
3.16
< 1.3
< 0.1
V&s
ReSi MosSi
_ _ < 0.35 _ _
MosSi MoSi,
_
CrsSi3 TcSi
TaSi2
Comp.
< 0.1
_ _
(K)
Tc
Mns Si3
P-W CsCl
P-W MoSi2
CrSi,
WsSi3
WsSi3
WsSi3
Mns Si3 CrSi2
WsSi3
W5Si3 FeSi
P-W WsSi3 NbeSu, MoSi, tetrag.
P-W
tetrag. FeSi
Mns Si3
Mns Si3 FeSi
CrSi2
StNCt.
V
+38
t37
+34
t34
+33 +34
t30
t30
+30
+30
t30
t30
+29 t29
+29
t29
t28 +29 +29
t28 t28
+28
+27
+26 i-27 +27
(J c
Silicides of transition metals with 5.6 and 7 outer electrons and thorium silicides.
Aluminides of transition metals with 5,6 and 7 outer electrons and thorium aluminides.
Comp.
Table 2
Table 1
1.4
< 0.02 _ _
< 1.15
16.8
< 1.2
-
_
< 1.2 _
< 0.35 _
< 1.2
-
< 1.2 _
_ _
_
< 1.2 _
-
< 1.2 _
11 May 1981
PHYSICS LRl-TERS
Volume 83A, number 2 Table 3 Germanides of transition metals. Comp.
U.&e3
MnsSia
ThGe
NaCl
0
UGe,
ZrSia
+5
ThGea
ZrSia
+6
ThaGe
CuAla
m3Ge2
Th3
-9
_ -
CrB orthor.
+12
-
+12
-
Cu3Au trigon. cubic
+13
d-GdSia
+17
0.87 1.49
+17
0.4
Ir4Ges Rh,,Geas
MnP tetrag. tetrag.
LaGea TiGe
a-SiaTh orthor.
HfGea
ZrSia
NbsGea Rh&% PdGe
MnsSia tetrag. MnP
IrGe TiaGe
MtlP Ni3P Ti3P orthor.
+20 +20
P-W MnP
+21 +21
ZrGea
ZrSia
+21
< 0.35
Hf3Ge
Ti3P
+21
< 1.8 1.3 -
IriGe7 LaCei PtGe
ZraGe OsaGea Nb3Ge RhGe
ZrSia ScGea Crr r Gers* tetrag.
+13 +15
< 0.35 -
< 1.2 -
+24 ~24
< 1.15
CrB CrB
+24
-
Fe2P
+25
< 1.2 -
ZraGe
hexag.
+25
< 1.8
Hf2Ge
CuAla
+25
< 0.05
Ws Sia
+26
CrSia Ua Si2
+26 +26
< 1.02 < 1.2 -
CrB
< 0.35 < 0.35
HfaGe, ScGe PdarGea
ptaa21
Zr5Q3
MnsSia
+26 +26 +26
MnsSia
+27
< 1.8
MoSi2 monocl.
+27 +27
-
+17
-
Hf&a p-MoGe2
+17
-
Pt3Ge
+18
2.24 _
RuGe
FeSi
+27
< 1.2 -
Scs Gea TieGes
Mns Sia orthor.
+27
-
+27 +27 +27 +27
< 1.2
+28 +28
-
+28
-
+18 +19 +19 +19 +19
+20 +21
+21 +22
2.2 -
CrrrGe8 CrGe*
CrsSia orthor. FeSi
Me-3
W&a
CrriQ3
< 0.35 4.7 < 1.7
Ta&a
< 1.8 -
VsGea
23.2 0.96
+22 +22
< 0.33
V17&31
monocl. tetrag.
MoGea
PbCla
+22
< 1.2
RU2 G3
orthor.
+22
NbGe2
CrSi2
+23
OsGea
+24
Nb&a TaGea
LaGe
--
+24
Pt2Ge
< 1.5 -
G)
TiSi2
< 0.1
+12
T,
MnsSia hexag.
< 0.07
+11
AV V
y&e3
+9
MnsSia
a-
TiGe2
+11
CaCls
UQ3
_ _.------
Sia
J-a@3
I&e4
stnlct.
____
NbroGe, YGe ZrGe
PtCea Pta Ge3
Comp.
2.1
oxides A1203 and Si02 on the grain or on the twin (if the crystal is twinned) boundaries [3].
vllGe8
WsSia Mns Si2 hexag.
TasGea Tis Gea
MnsSia MnsSia
+29 +29
PdzsGea
trigon. ThSi2 Fe2P
+29 +29
P-W orthor.
+31
%a3 Y&3
ya2
Pd,Ge Mo3Ge
3.0
+28
+30
< 1.2 3.8 < 0.35 1.5 2.12
W&a
+31 +32
-
m2G
PbC12
+33
-
v3Ge
P-w
+37
CraGe
P-W
+38
6.1 < 1.2 --.--
References [l] I.M. Chapnik, Philos. Mag. B37 (1978) 397.
79
Volume 83A, number 2 [2] [3] [4] [5]
PHYSICS LETTERS
I.M. Chap&, J. Mater. Sci. 12 (1977) 422. I.M.Chapnik, J. Mater. Sci. 15 (1980) 3175. N.F. Mott, Philos. Mag. 6 (1961) 287. D. Tuomi, Proc. 14th Intersociety energy conversion engineering Conf. (Boston, USA, August 1979) Part II (IEEE, New York 1979). [6] I.M. Chapnik, Phys. Stat. Sol. (a) (1980) K193. [7] B.W. Roberts, J. Phys. Chem. Ref. Data 5 (1976) 581.
80
11 May 1981
[8] I.M. Chapnik, Philos. Mag. 32 (1975) 673. [9] I.M. Chap&, J. Mater. Sci. 14 (1979) 2022. [lo] J.P. Charlesworth, Phys. Lett. 21 (1966) 501. [ 111 G. Arrenius, R. Fitzgerald, D. Hamilton, B.A. Holm and B.T. Matthias, J. Appl. Phys. 35 (1964) 3487. [ 121 T. Claeson and J. Ivarsson, J. Appl. Phys. 48 (1977) 3998.