THERMAL CONDUCTIVITY OF MG (B0.98C0.03)2 ROLE OF ELECTRON AND IMPURITY SCATTERING AND SUPERCONDUCTING STATE OF SPECIFIC HEAT OF MG1‐XALXB2, (0< X < 0.3) SUPERCONDUCTORS

Swati Bhatnagar

Abstract


We use the Kubo model to calculate the lattice contribution to the thermal conductivity (κph) in Mg(B0.98C0.03)2superconductors. The theory is formulated when heat transfer is limited by the scattering of phonon from defects, grain boundaries, charge carriers, and phonons. Later on, the carrier (electron) contribution to the thermal conductivity (κe) is calculated within relaxation time approximation for π and σ band carriers with s wave symmetry. Such an estimate sets an upper bound on κe and a very small contribution is seen for total heat transfer at room temperature. a theoretical analysis of specific heat C(T)behavior of theof Mg1xAlxB2, (0< x < 0.3) in the temperature domain 0 ≤ T ≤ 300 K is presented. Calculations of C (T) have been made within the two‐component scheme: one is the phonon and the other is Electronic contribution. Phonon specific heat is well estimated from the Debye and Einstein temperature for Mg1xAlxB2, obtained following an overlap repulsive potential. The interatomic potential of this model includes contributions from the long‐range Coulomb attraction and the short‐range overlap repulsion and the van der Waals attraction.


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