Be-doped TlBa
2(Ca
2−yBe
y)Cu
3O
10−δ (
y=0, 0.25, 0.5, 0.75, and 1.0) superconductor bulk samples were synthesized by solid state reaction and characterized by X-ray diffraction (XRD), dc-resistivity {
ρ (Ω cm)}, and Fourier Transform Infrared (FTIR) absorption spectroscopy. Fluctuations induced conductivity (FIC) analysis is carried out on temperature dependent dc-resistivity data of as-prepared and oxygen post-annealed TlBa
2(Ca
2−yBe
y)Cu
3O
10−δ superconductor samples by using Aslamazov–Larkin (AL) and Lawrence–Doniach (LD) models for excess conductivity. Different microscopic parameters such as zero temperature coherence length along
c-axis {ξ
c(0)}, inter-layer coupling (
J), inter-grain coupling (
α), critical exponent (
λD) and dimensionality of fluctuations are calculated for understanding the role of Be-doping on superconducting properties of TlBa
2(Ca
2−yBe
y)Cu
3O
10−δ samples. The cross-over temperature (
To) is shifted towards higher temperature values with the increase of Be contents in TlBa
2(Ca
2−yBe
y)Cu
3O
10−δ samples. The increase in
ξc(0) and
J after Be-doping at Ca sites shows the improvement of inter-plane coupling in TlBa
2(Ca
2−yBe
y)Cu
3O
10−δ samples. The increase in zero resistivity critical temperature {
Tc(R=0) (K)} up to
y=0.5 and then decrease for
y=0.75, 1.00 fixed the Be-doping level for optimum increase of superconducting properties of TlBa
2(Ca
2−yBe
y)Cu
3O
10−δ samples. The appreciable changes in all the microscopic parameters extracted from the FIC analysis and the increase in relative intensity of almost all the oxygen phonon modes indicate the oxygen diffusion in the unit cell after oxygen post-annealing the samples. The oxygen diffusion can take place at both inter-granular and intra-granular sites, which increase the superconducting volume fraction by improving the grains size, inter-grain connectivity and carrier density.
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