 |
2.6 Electricity and magnetism
2.6.1 Electrical resistivities
The electrical resistivity or specific resistance
ρ is the resistance between the opposite faces of a metre cube of a
material. The values given below are in ohm metre units (Ω m). The
reciprocal of ρ is the electrical conductivity.
The electrical resistivity is readily influenced and
usually increased by factors such as impurity content, porosity, cold work,
irradiation, etc. The values given in the main table relate to samples for
which such effects are usually minimal. For similar reasons values are not
given below 78.2 K, since the effects of impurities, etc., become
increasingly important the lower the temperature and finally determine the
so-called residual resistance eventually attained for many metals. Certain
metals, however, become superconducting below a certain temperature (see
section 2.6.4), and for such metals the transition temperature is entered
after the name of the metal. For the influence of magnetic fields upon
resistance, see section 2.6.6.
In the main table, values given in italics are for the
liquid phase. All other values are for a polycrystalline solid sample. For some
non-cubic metals, a separate table indicates the degree of electrical
resistivity anisotropy reported for single crystals at normal temperature. A
similar degree of anisotropy can be expected throughout the temperature range
of the particular crystal form.
Semi-conducting elements are also listed separately, and
again only for normal temperature. Since the electrical resistivities of these
poor conductors are so strongly dependent on the small amounts of impurity that
may be added intentionally or be present inadvertently, the published values
differ considerably, as may the value for any specific sample. The table
indicates an approximate value or a likely range of values.
Other elements which are solid at normal temperature and
do not conduct electricity are dealt with under electrical insulators (see section
2.6.2). These include boron, carbon in the form of diamond, iodine,
phosphorus and sulphur. Elements which are gases at normal temperature and
pressure are also omitted.
Values are also given for a few typical alloys. These
are mainly the alloys for which thermal conductivity data were given and
further compositional details will be found in section 2.3.7.
Resistivities of metallic elements
|
Metal |
ρ(10−8 Ω
m) |
|
Temperature/K |
|
78.2 |
273.2 |
373.2 |
573.2 |
973.2 |
1473.2 (or other) |
|
|
|
|
|
|
|
|
|
Aluminium (1.17 K) |
0.229 |
2.42 |
3.57 |
5.83 |
25.5 |
33.1 (1500 K) |
|
Antimony |
8 |
39 |
59 |
— |
114 |
123.5 (1273 K) |
|
Arsenic |
5.5 |
26 |
— |
— |
— |
— |
|
Barium |
6.65 |
30.2 |
46.5 |
90.8 |
— |
— |
|
Beryllium |
0.72 |
3.02 |
5.92 |
12.2 |
26.5 |
— |
|
Bismuth |
35 |
107 |
156 |
129 |
155 |
172 (1273 K) |
|
Cadmium (0.54 K) |
1.6 |
6.8 |
9.8 |
— |
— |
36.3
(873.2 K) |
|
Calcium |
0.63 |
3.11 |
4.75 |
7.8 |
20 |
— |
|
Cerium |
— |
73 |
80 |
92 |
110 |
123 (1053 K) |
|
Caesium |
4.06 |
18.8 |
44.5 |
67.3 |
128 |
338 (1500 K) |
|
Chromium |
0.5 |
12.7 |
16.1 |
25.2 |
47.2 |
80 |
|
Cobalt |
0.9 |
5.6 |
9.5 |
19.7 |
48 |
88.5 |
|
Copper |
0.204 |
1.54 |
2.22 |
3.59 |
6.55 |
21.3
(1356 K) |
|
Dysprosium |
26 |
89 |
103 |
124 |
156.5 |
184 |
|
Erbium |
41 |
81 |
103 |
135 |
183 |
216 |
|
Europium |
60 |
89 |
— |
— |
— |
— |
|
Gadolium |
20 |
126 |
— |
— |
— |
— |
|
Gallium (1.1 K) |
2.75 |
13.6 |
27.2 |
31 |
— |
— |
|
Gold |
0.468 |
2.05 |
2.88 |
4.61 |
8.59 |
33.4
(1500 K) |
|
Hafnium (0.35 K) |
6.55 |
30.4 |
44.3 |
74.6 |
126 |
164 (1500 K) |
|
Holmium |
34 |
90 |
105 |
134 |
175 |
203 |
|
Indium (3.35 K) |
1.8 |
8.0 |
12.1 |
36.7 |
47 |
55 (1273 K) |
|
Iridium (0.14 K) |
0.9 |
4.7 |
6.8 |
10.8 |
22 |
33.5 |
|
Iron |
0.64 |
8.57 |
14.4 |
30.2 |
85.7 |
118 (1400 K) |
|
Lanthanum (4.71 K) |
— |
54 |
66 |
83 |
105 |
126 (1173 K) |
|
Lead (7.2 K) |
4.7 |
19.2 |
27 |
50 |
108 |
126
(1273 K) |
|
Lithium |
0.93 |
8.53 |
12.4 |
28.5 |
39.0 |
53 (1500 K) |
|
Lutetium |
16 |
54 |
— |
— |
— |
— |
|
Magnesium |
0.53 |
4.05 |
5.74 |
9.0 |
15.4 |
28.7 (1173 K)
|
|
Manganese |
132 |
143 |
147 |
152 |
— |
— |
|
Mercury (4.12 K) |
5.8 |
94.1 |
103.5 |
128 |
214 |
630 |
|
Molybdenum (0.92 K) |
0.454 |
4.85 |
7.34 |
12.5 |
23.3 |
38.4 (1500 K) |
|
Neodymium |
— |
61 |
74 |
93 |
120 |
138 (1183 K)
|
|
Neptunium |
— |
— |
119.3 |
— |
— |
121.3 (811.2 K) |
|
Nickel |
0.51 |
6.16 |
10.5 |
23.1 |
40.7 |
57 (1600 K)
|
|
Niobium (9.1 K) |
3.0 |
15.2 |
19.2 |
27.1 |
43 |
59 |
|
Osmium (0.65 K) |
— |
8.1 |
11.4 |
17.8 |
30.4 |
46 |
|
Palladium |
1.67 |
9.8 |
13.5 |
20.2 |
31.3 |
43 (1600
K) |
|
Platinum |
1.96 |
9.81 |
13.6 |
21.0 |
34.3 |
48.3 |
|
Plutonium |
~ 150 |
146 |
142 |
109 |
— |
— |
|
Polonium |
— |
~ 40 |
— |
— |
— |
— |
|
Potassium |
1.30 |
6.49 |
15.8 |
27.7 |
64.7 |
165 (1500
K) |
|
Praseodymium |
— |
65 |
78 |
96 |
118 |
134 (1123 K) |
|
Promethium† |
— |
50 |
64 |
89 |
126 |
— |
|
Protactinium (1.4 K) |
6.1 |
17.7 |
— |
— |
— |
— |
|
Rhenium (1.7 K) |
2.62 |
17.2 |
24.9 |
39.7 |
63.5 |
84.4 |
|
Rhodium |
0.46 |
4.3 |
6.2 |
10.2 |
20 |
33 |
|
Rubidium |
2.59 |
11.5 |
27.3 |
45.1 |
93 |
250 (1500
K) |
| Ruthenium
(0.49 K) |
1.34 |
7.1 |
10.0 |
15.6 |
27.8 |
44.4 |
|
Samarium |
66 |
91.4 |
— |
— |
— |
— |
|
Scandium |
— |
50.5 |
75 |
115 |
167 |
198 |
|
Silver |
0.278 |
1.47 |
2.07 |
3.34 |
6.10 |
18.7 (1400 K)
|
|
Sodium |
0.76 |
4.33 |
9.51 |
17.4 |
38.9 |
88 (1500
K) |
|
Strontium |
3.55 |
12.3 |
16.7 |
25.5 |
|
— |
|
Tantalum (4.48 K) |
2.53 |
12.2 |
16.9 |
26.3 |
43.2 |
63 (1500 K) |
|
Technetium (11.2 K) |
— |
— |
22.6 |
33.3 |
51 |
65 |
|
Terbium |
27 |
113 |
— |
— |
— |
— |
|
Thallium (2.37 K) |
3.7 |
15 |
22.8 |
38 |
85 |
88 (1073
K) |
|
Thorium (1.37 K) |
3.9 |
14.7 |
20.8 |
32.5 |
53.6 |
68 |
|
Thulium |
31 |
67 |
— |
— |
— |
— |
|
Tin (3.69 K) |
2.1 |
11.5 |
15.8 |
50 |
60 |
72 |
|
Titanium (0.39 K) |
4.6 |
39 |
58 |
90 |
142 |
— |
|
Tungsten (0.01
K) . . . . . . |
0.573 |
4.82 |
7.19 |
12.3 |
23.7 |
40.3 (1500 K) |
|
Uranium (0.68 K)
. . . . . . |
11 |
28 |
35 |
47 |
— |
— |
|
Vanadium (5.03 K)
. . . . . |
2.30 |
18.1 |
25.9 |
39.5 |
63.1 |
89 (1500 K) |
|
Ytterbium . . . . . . . . . |
13 |
27.7 |
— |
— |
— |
— |
|
Yttrium . . . . . . . . . |
15.5 |
55 |
— |
— |
— |
— |
|
Zinc (0.85 K)
. . . . . . . |
1.04 |
5.48 |
7.96 |
13.3 |
|
37 (873.2 K) |
|
Zirconium (0.55 K)
. . . . . . . |
6.36 |
38.8 |
55.9 |
87.7 |
128 |
120 (1500 K) |
|
|
|
|
|
|
|
|
† Estimated values based on R.
K. Williams and D. L. McElory, USAEC, ORNL-TM-1424, 1966.
Resistivities of semi-conducting elements at
normal temperature
|
Carbon |
ρ/(Ω m) |
Other elements |
ρ/(Ω m) |
|
|
|
|
|
|
Amorphous |
~ 6 × 10−5 |
Germanium |
(1 − 500) 10−3 |
|
Graphite |
(3−60)
× 10−6 |
Selenium |
~ 0.1 |
|
Pyrolytic graphite, along planes |
~ 5 × 10−6 |
Silicon |
(1 − 600) × 10−1 |
|
,, ,, normal
to planes |
~ 5 × 10−3 |
Tellurium |
~ 3 × 10−3 |
|
|
|
|
|
Resistivities of single crystals of some
non-cubic metals at normal temperature
|
Metal |
ρ/(10−8 Ω m)
in direction of |
| c-axis |
a-axis |
b-axis |
|
|
|
|
|
|
Antimony . . . . . . . . . . . . |
35.6 |
42.6 |
|
|
Beryllium . . . . . . . . . . . . |
3.58 |
3.13 |
|
|
Bismuth . . . . . . . . . . . . |
138 |
109 |
|
|
Cadmium . . . . . . . . . . . . |
7.79 |
6.54 |
|
|
Dysprosium . . . . . . . . . . . |
77.4 |
98.2 |
|
|
Erbium . . . . . . . . . . . . . |
47.0 |
87.6 |
|
|
Gadolinium . . . . . . . . . . . . |
122 |
135 |
|
|
Gallium . . . . . . . . . . . . . |
55.5 |
17.3 |
7.85 |
|
Holmium . . . . . . . . . . . . . |
59.9 |
101.2 |
|
|
Lutetium . . . . . . . . . . . . . |
34.0 |
75.6 |
|
|
Magnesium . . . . . . . . . . . . |
3.78 |
4.53 |
|
|
Mercury (at 227.7
K) . . . . . . . . . .
|
17.7 |
23.5 |
|
|
Tellurium . . . . . . . . . . . . . |
56 000
|
15 400 |
|
|
Terbium . . . . . . . . . . . . . |
101 |
122 |
|
|
Thulium . . . . . . . . . . . . . |
46 |
87 |
|
|
Tin . . . . . . . . . . . . . . |
13.1 |
10.0 |
|
|
Zinc . . . . . . . . . . . . . . |
6.05 |
5.83 |
|
|
|
|
|
|
Resistivities of some typical
alloys
|
Alloy† |
ρ/(10−8 Ω
m) |
|
Temperature/K |
|
273.2 |
373.2 |
573.2 |
973.2 |
1473.2 |
|
|
|
|
|
|
|
|
Alpax
gamma‡ . . . . . . . . . |
3.5 |
5.0 |
7.85 |
— |
— |
|
Alumel . . . . . . . . . . . |
28.1 |
34.8 |
43.8 |
53.2 |
65.1 |
|
Brass . . . . . . . . . . . . |
6.3 |
— |
— |
— |
— |
|
Bronze
. . . . . . . . . . . |
13.6 |
— |
— |
— |
— |
|
Chromel
P . . . . . . . . . . . |
70.0 |
72.8 |
79.3 |
89.3 |
100.1 |
|
Constantan . . . . . . . . . . |
49 |
— |
— |
— |
— |
|
German
silver . . . . . . . . . . |
40 |
— |
— |
— |
— |
|
Lo–Ex‡ . . . . . . . . . . . |
3.95 |
5.45 |
8.55 |
— |
— |
|
Manganin . . . . . . . . . . . |
41.5 |
— |
— |
— |
— |
|
Monel . . . . . . . . . . . |
42.9 |
50.1 |
52.5 |
63.3 |
— |
|
Nichrome . . . . . . . . . . . |
107.3 |
108.3 |
110.0 |
110.3 |
— |
|
RR
59† . . . . . . . . . . . |
3.5 |
4.9 |
7.6 |
— |
— |
|
RR
77‡ . . . . . . . . . . . |
3.95 |
5.2 |
7.8 |
— |
— |
|
Steel,
Carbon . . . . . . . . . . |
17.0 |
23.2 |
39.8 |
93.5 |
123.1 |
|
,,
18/8 . . . . . . . . . . |
66.3 |
74.3 |
89.1 |
109.4 |
124 |
|
,, Era
ATV . . . . . . . . . |
98.0 |
102.7 |
111.0 |
122.0 |
— |
|
,,
Ni–Cr . . . . . . . . . . |
27.7 |
33.7 |
48.7 |
99.4 |
122.2 |
|
,, Silicon
. . . . . . . . . . |
41.9 |
47.0 |
60.1 |
105.7 |
127.1 |
|
,,
Stainless . . . . . . . . . |
55.0 |
63.4 |
80.2 |
114.1 |
— |
|
Pt 90%, Ir 10% . . . . . . . . . |
24.8 |
28.0 |
— |
— |
— |
|
Pt 90%, Rh 10% . . . . . . . . . |
|
