α-Irradiation induced changes in fluctuation-conductivity in (Bi, Pb)-2223 superconductors

Effect of γ-irradiation on the transport and structural properties of polycrystalline Bi1.2 Pb0.33 Sr1.54 Ca2.06 Cu3 O10+δ superconductor

“…Our findings show that MT theory is not much suitable for explaining excess conductivity data with the same indicating that pair breaking is not the major phenomenon in the case of γ-irradiated sample. Similar findings have been observed by other researchers [16] also in case of α-irradiation on Bi-2223 sample.…”

“…We have estimated the two-dimensional characteristic length (d), based on structural characteristic of our sample. The value of d is taken half of the lattice parameter c, as considered by many other researchers [14,16]. It is believed that the value d should be greater than the thickness ∼4.5 Å of the double CuO 2 planes, but smaller than the c-axis unit cell size (36.91 Å for this case).…”

“…Because of their extremely small coherence length, quasi two-dimensional layered structure and high-superconducting transition temperature, the thermodynamic fluctuations take role in affecting different properties like electrical conductivity, thermoelectric power etc. [11][12][13][14][15][16] of high-T c superconductors. In case of electrical conductivity, this fluctuation manifests as excess conductivity.…”

Annealing effect on the excess conductivity of Cu0.5Tl0.25M0.25Ba2Ca2Cu3O10−δ (M = K, Na, Li, Tl) superconductors

“…We have obtained the T mf c from the point of inflection of the dp=dT versus T plot, which has been shown to be a good choice for the FIC investigations. [23][24][25][26] Maki-Thompson contributions are absent in our high temperature superconductors due to large pair breaking effects arising from the inelastic electron scattering. 27 On the other hand, it has often been difficult to choose the temperature range for fitting due to various possible contributions to the variation of Dr with temperature, T. The Cu-and Tl-based superconductors are well known for their lower anisotropy, 28-33 so the intergrain resistivity does not contribute much to the fluctuations.…”

“…35 We have synthesized and studied the effect of oxygen annealing on the excess conductivity of Cu 0.5 Tl 0. 25 low electro-negative, alkali metals doped in the charge reservoir layer are expected to liberate their outermost electrons easily, which could supply a negative charge to hole-doped conducting CuO 2 planes. This electronic charge may reduce the carrier density by neutralizing the holes there.…”