Alain Junod

TL;DR: In this article, the irreversibility of the magnetization and the low temperature specific heat of high purity YBa2Cu3O7−δ crystals was investigated and it was shown that the heat treatment that suppresses the magnetic "fishtail" effect also suppresses Schottky component of the heat capacity.

Abstract: Homogeneous Tl 2 Ba 2 CuO x ceramics were synthesized by a novel route allowing tight control of thallium losses, starting from Tl 2 Ba 2 O 5 precursors and using high gas pressures. Annealing followed by fast quenching into gallium allowed us to map the critical temperature (0 to 92 K) and the crystal symmetry (orthorhombic or tetragonal) in the (T;p(O 2 )) plane. The orthorhombic phase is found to be stoichiometric, whereas the tetragonal phase has a homogeneity domain in the thallium concentration. The critical temperature, determined by the oxygen concentration, is not sensitive to the crystal structure. Selected physical properties of Tl 2 Ba 2 CuO x compounds are presented.

TL;DR: Under moderately high oxygen pressure (90 bar, 950 °C), two new compounds appeared in the YBa-Cu-O system: Ba2Cu3O5+δ and Y2Ba9Cu6Oz as discussed by the authors.

TL;DR: In this paper, the inversion of the Eliashberg equations was applied to calorimetric data in the superconducting state, yielding integrals of the spectral function of the electron-phonon interaction α2F(ω).

TL;DR: In this article, the stability of the Y2Ba4Cu7Ox phase (Y-247) has been investigated under pure oxygen pressures up to 1700 bar, and the effect on the susceptibility is as expected (χ becomes temperature independent) but surprisingly, Tc saturates at 95K.