Temperature Dependence of Some Fundamental Physical Quantities in YBa2Cu3O7

Abstract
The resistivity and Hall coefficient of YBa2Cu3O7 were measured as a function of temperature. The data obtained were analyzed with a conductivity model of a diffusion type: σ x x =n e 2 D/2k B T. It is found that the carrier concentration n of hole type varies as n=n 0[1+αT] with the magnitude ratio αT>1 at T>T c, and consequently the diffusion constant D varies as D∝1/n. Therefore, in terms of the relaxation time τ, it becomes 1/τ=A T+B T 2. The origin of two terms is discussed.