Oxygen Phonon Branches in Detwinned YBa2Cu3O7

v 2 [ co nd - m at . s up r - co n ] 1 6 Se p 20 02 Oxygen Phonon Branches in Detwinned YBa

3D-XY critical fluctuations of the thermal expansivity in detwinned YBa2Cu3O7-δ single crystals near optimal doping

The strong coupling of superconductivity to the orthorhombic distortion in YBa2Cu3O7-δ makes possible an analysis of the superconducting fluctuations without the necessity of subtracting any background. The present high-resolution capacitance dilatometry data unambiguously demonstrate the existence of critical, instead of Gaussian, fluctuations over a wide temperature region (± 10 K) around Tc....

Phonon and magnetic neutron scattering at 41 meV in YBa2Cu3O7.

We report inelastic neutron scattering measurements at excitation energies h̄v , 41 meV in YBa 2Cu 3O 7. We separate magnetic and phonon contributions to the scattering cross section by a detailed analysis of the momentum dependence of the scattered intensity. The previously reported broad peak around q ­ spya, pyad in the normal state can be entirely accounted for by a phonon which primarily in...

Investigation of A1g phonons in YBa2Cu3O7 by means of LAPW atomic–force calculations

We report first–principles frozen–phonon calculations for the determination of the force–free geometry and the dynamical matrix of the five Raman–active A1g modes in YBa2Cu3O7. To establish the shape of the phonon potentials atomic forces are calculated within the LAPWmethod. Two different schemes – the local density approximation (LDA) and a generalized gradient approximation (GGA) – are emplo...

بررسی اثر کمبود اکسیژن، گذار فاز ساختاری ارتورمبیک‌ - تتراگونال‌ و ساختار نوار انرژی در ترکیب YBa2Cu3O7-& delta

  Obtaining the superconductor samples or mainly, structural phase controlling in 123 systems is a matter of special importance. As decreasing of oxygen in this structure has special effects, and mainly causing structural phase transition, by investigating the structure and thermal analysis of the system, tetragonal-orthorhombic structural phase transition was observed and optimum contents of s...