[SI-LIST] Re: Effect of Temperature on Metal Conductivity
- From: Abdulrahman Rafiq <arafiq786@xxxxxxxxx>
- To: zhang_kun@xxxxxxxxxx, si-list <si-list@xxxxxxxxxxxxx>
- Date: Thu, 25 Nov 2004 00:49:55 -0800
Zhangkun
Conductivity of a pure, defect-free metal is determined by the
electrical structure of the atoms. However, we can change the
conductivity by influencing carrier mobility (mu). Where mobilioty
(mu) is proportional to the drift velocity--which is low if the
electrons collide with imperfections in the lattice.
Recall that a mean free path is the average distance b/w collisions;
hence a long mean free path permits high mobilities and
high-conductivities, and therefore low resistivity.
So How does Temperature effect a metals conductivity?
With increased temperature in a metal, thermal energy causes atoms in
metal to vibrate, in this excited state atoms interact with and
scatter electrons. Thus decreasing the mean free path, and hence the
mobiloty of electrons too decreases, and resistivity increases.
Since resistivity = 1/conductivity
Therefore change in resistivity with Temperature:
(Resistivity due to termal vibrations only) = (Resistivity at Room
Temp, 25 deg-C) X {(temp resistivity coefficient)(delta T)}
The (temp resistivity coefficient) for some metals are:
Copper (cu) = 0.0068 [Ohm cm/deg-C]
Aluminum (Al) = 0.0043 [Ohm cm/deg-C]
Nickel (Ni) = 0.0069 [Ohm cm/deg-C]
Gold (Au) = 0.0040 [Phm cm/deg-C]
Hope this helps
Thanks
Abdulrahman Rafiq
On Mon, 22 Nov 2004 14:00:02 +0800, Zhangkun <zhang_kun@xxxxxxxxxx> wrote:
> Dear All
> Is there any effect of temperature on metal conductivity? In another word,
> does the resistance of metal change with the temperature? How much?
>
> Best Regards
>
> Zhangkun
> 2004.11.22
>
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Abdulrahman Rafiq
arafiq@xxxxxxxxxxxx
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