Elastic constants, debye temperatures, and electron-phonon parameters of superconducting cuprates and related oxides

Abstract

Abstract Using both measurements and modeling, we studied the cohesive and related properties of several oxides. Superconducting oxides include La1.85Sr0.15CuO4, Y1Ba2Cu3O7, and (Bi-Pb)2Sr2Ca2Cu3O10. Related nonsuperconducting oxides include SrTiO3, BaTiO3, and La2CuO4. For these materials, we give the complete quasiisotropic elastic constants corrected to the void-free state. From elastic constants and atomic volume, we calculated Debye characteristic temperatures, Θ D . Using Kresin's model, valid for all values of the electron-phonon parameter, λ, we estimated I from Tc and Θ D . For the superconducting cuprates, λ ranges from 1.3 (La-O) to 10.0 (Tl-O). Except perhaps for Tl-O, these parameters fall within a range predicted by theory. For all the above materials, we show the 295–5-K variation of Θ D . We support our elastic-constant measurements with Born-model calculations of the bulk modulus. Key Words: Born modelbulk moduluscuprate superconductorsDebye temperatureelastic constantselectron-phonon parameterKresin modelOxidessuperconductors