Thermodynamic properties and superconductivity of Ohmic materials

✍ Scribed by Alfred A. Wolf

• Publisher: Elsevier Science
• Year: 1970
• Tongue: English
• Weight: 831 KB
• Volume: 289
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/0016-0032(70)90285-1

✦ Synopsis

It is established from the Jirst and second laws of thermodynamics that Ohm'8 law is thermodynamically valid only under an isothermal process, a result knoum. empirically since the discovery of this law. Furthermore, in an Ohmic material the ratio of the Helmjholtz free energy of the material to the total energy density (total energy per unit Ohm) is a constant and this constant turns out to be the resistance of the material.

It is also shown that if an Ohmic material becomes a superconductor then its transition tem,perature is directly proportional to its net internal energy and inversely proportional to its entropy.

This implies that for superconducting Ohmic material, in which the intemzal energy is high and the entropy is low, the transition temperature will be high. Although this relationship between transition temperature, internal energy and entropy does not predict the transition temperature, it does give an appreciation for the factors involved and therefore one can conjecture that high temperature superconductors are possible. Furthermore, as shown in. (a), if the ordering of the material is improved, the transition temperature increases.