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A new transport theory for high temperature superconductors is propos#ed and supported with extensive calculations. The Cooper-pairs while remaining on a pseudo Fermi surface behave like weak Fermions. When the Cooper-pairs become free they behave as spinless bosons. The polarons and bipolarons are highly localized quantum states with virtually no gap existing in between them and are considered as bosons with nondegenerate spining. The binding energies of Cooper-pairs both in a weak Fermion system and for a spinless boson are calculated. A kind of a semimetallic softening transition is responsible for high temperature superconductivity and is temperature independent. There is no electron–phonon coupling for high temperature superconductors. High temperature ceramic superconductors before the onset of superconductivity are found to be Mott–Hubbard dielectric insulating materials.

Thermoelectric power (TEP) measurements were carried out on six samples of LQA alloys from two different series, namely FeZr and Fe(Co)B, at relatively low temperatures. A profile of the TEP shows a Gaussian trend in our observations for each specimen. The scattering centres are the major contributors to the residual TEP. Ziman theoretical model was used to estimate TEP; it is found that Ziman Theory fails to account for quantitative TEP measurements, at relatively low temperatures (77

A Gaussian trend is observed in the profile of thermoelectric power TEP for LQA alloys FeZr, studied in the relatively high temperature range, 350–760 K. The scattering centres are mainly responsible for the residual TEP. Ziman's theoretical model was applied to estimate the TEP from resistivity data. The microscopic changes in the specimens are associated with dynamic recovery processes and formation of vacancies and interstitials.

Electrical resistivity measurements in Iron-Zirconium liquid quinched amorphous alloys, in the temperature range 273 K ≤ T ≤ 900 K, show temperature dependent nucleus size. For Fe 20 Zr 80 , Fe 24 Zr 76 and Fe 35 Zr 65 LQA alloys the nucleus is ascribed to triple, double and single stage metal-insulator transitions respectively. These temperature dependent transitions define a curved Arrhenius plot.

Activation energies determined from Arrhenius plot for cobalt-boron liquid quenched amorphous alloys in the temperature range 40 K < T < 300 K , suggest vacancy and interstitial formation to nucleate crystalline phases in an amorphous matrix preferably at sites where dangling bonds are present. Nucleation of crystallites with preferential tetragonal or orthorhombic structures is a self-evolving process due to catalytic presence of dangling bonds in an amorphous material and that the occurrence of negative activation energies support this evidence.

Electrical resistivity measurements of amorphous ( Fe x Co 100-x)83 B 17 alloys in the temperature range 40 K < T < 300 K have been obtained. We observed from the analysis of the resistivity data that there is no s-d interaction or Js-d coupling. An empirical relationship for estimating Θ D is suggested from the normalized electrical resistivity data, which holds good both for theoretical and estimated Θ D . For s-d interaction or Js-d coupling to occur in ferromagnetic amorphous alloys, ordering of ferromagnetic domains, i.e. Heisenberg interaction in a disordered matrix, would require temperatures of T ≤ Θ D /50 ≃ 0.02 Θ D .

We have prepared the bulk samples of 2223 Bi–Pb–Sr–Ca–Cu–O superconductor with a T c of 106 K. Temperature dependence of electrical resistivity and thermoelectric power (TEP) measurements were performed on the samples. The behaviour of thermoelectric power near and above the transition temperature can be described on the basis of thermodynamic fluctuations of superconducting order parameter.