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Temperature coefficient of resistance - size effects vs bulk

  1. Jun 19, 2015 #1
    I am looking for a reference to discuss the effects of resistor size on alpha, the temperature coefficient of resistivity.
    If we use the linear R=R0*(1+alpha*(T-T0))
    alpha is a material constant, presumably for bulk-type resistors. Will alpha change as size (cross sectional area) of the resistor shrinks to tens of nanometers in one dimension? any reference on this? thanks
     
  2. jcsd
  3. Jun 19, 2015 #2

    Baluncore

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    Alpha is a material constant that is independent of the dimensions.
     
  4. Jul 7, 2015 #3
    I concluded something different, based on literature.

    http://iopscience.iop.org/1347-4065/9/11/1326


    there is also the fuchs-sondheimer theory but i dont think it dicusses alpha
     
  5. Jul 7, 2015 #4

    Baluncore

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    I cannot access that article because it is behind a pay-wall.

    The abstract refers to resistivity as being determined by surface roughness in thin films. I would interpret that as a “virtual thickness” parameter, not as a change in the bulk material resistivity.

    Although the abstract mentions the temp-co was also studied, it reveals no temp-co effect due to thickness. That might suggest that there was no significant effect on alpha observed.
     
  6. Jul 7, 2015 #5
    I can't attest to the quality of the article but it has the suggestion that alpha may have some dependence on the physical dimensions of the sample.

    I think a difference in the effect of surfaces and grains on the scattering of electrons and scattering or localization of phonons could conceivably contribute to changes in alpha as a function of surface:volume ratio or some other size parameter.

    for completeness, from the article
    Here h is the amplitude of oscilations describing the surface roughness and lambda is the mean-free-path of electrons.
    Alpha-thickness.png
    definition%20of%20h.png
    if you are really interested in the article let me know and i can send you a dropbox link or something
     
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