Electrical transport anisotropy of uniaxial polycrystalline samples and the effective medium approximation: An application to HTS

Electrical effective parameters of the grains and the Montgomery's method in $$\hbox {Bi}_{1.65}\hbox {Pb}_{0.35}\hbox {Sr}_2\hbox {Ca}_{2.5}\hbox {Cu}_{3.5}\hbox {O}_y$$ Bi 1.65 Pb

“…From the results, versus J curves are built and paracoherent resistivity tensor component was determined by taking the resistivity value at the point where the slope of the ρ-J curve starts to decrease. This way, we are avoiding the "contamination" of the measurements due to the presence of intragranular dissipation sources [7,8].…”

“…Under these conditions, it was possible to determine the effective 1 3 anisotropy at sample level, = z ∕ x , which resulted to be ( ≥ 18) [7]. Afterwards, by using an effective medium approximation model applied to electric transport measurements of the polycrystals [7,8], the effective anisotropy of the grains [7], t = c ∕ ab , their orientation probability, xa , the weak links resistivity, wl , and the slope of the temperature dependence of the grains' resistivity, A ab = ab ∕ T were determined. Here, c , ab and T are the out-of-plane resistivity, the in-plane resistivity and the temperature of the samples, respectively [7].…”