Strain effects on point defects and chain-oxygen order-disorder transition in 123 cuprate compounds

Abstract

The energetics of Schottky defects in 123 cuprate superconductor series, REBa2Cu3O7 (where RE = lanthandies) and YAE2Cu3O7 (AE = alkali-earths), were found to have unusual relations if one considers only the volumetric strain. Our calculations reveal the effect of non-uniform changes of interatomic distances within the RE-123 structures, introduced by doping homovalent elements, on the Schottky defect formation energy. The energy of formation of Frenkel Pair defects, which is an elementary disordering event, in 123 compounds can be substantially altered under both stress and chemical doping. Scaling the oxygen-oxygen short-range repulsive parameter using the calculated formation energy of Frenkel pair defects, the transition temperature between orthorhombic and tetragonal phases is computed by quasi-chemical approximations (QCA). The theoretical results illustrate the same trend as the experimental measurements in that the larger the ionic radius of RE, the lower the orthorhombic/tetragonal phase transition temperature. This study provides strong evidence of the strain effects on order-disorder transition due to oxygens in the CuO chain sites.

Interconnection of the parameters obtained from the dielectric spectrum of CaF2 doped with ErF3 and YbF3

“…Furthermore, the cBΩ model was found [25] to enable the explanation why the defect formation enthalpy, in various categories of solids, is interconnected with the melting temperature. The model also describes the formation volume of Schottky defects in high c Τ superconductors [26] and is consistent with the measured trend [27] of melting temperatures for the RBa 2 Cu 3 O 7-δ (R-123, R = yttrium and lanthanides) cuprate high c Τ superconductors. Recent applications of the cBΩ model can be found in Ref.…”

Strong correlated pinning at high growth rates in YBa2Cu3O7−x thin films with Ba2YNbO6 additions

“…15 As shown in Table I, the BYNO films have similar selffield J c values at 77 K to the pure YBCO sample, except for the 10 Hz sample which is slightly reduced (1.2 MA cm À2 cf. $1.4-1.6 MA cm À2 ) compared to the others.…”

Study of grain boundary transparency in(Yb1−xCax)BLi1, Abraimov2, Polyanskii3 et al. 2015Phys. Rev. B140130View full textAdd to dashboardCite

“…c(x,y) is renormalized to bulk Ca-doping level c 0 , which is 0.3 here. Driven by local strain field and charge imbalance near GB, Ca segregates to the core regions while the channels between cores are low in Ca [7,[11][12][13][14][15] , the peak Ca concentraion in (YbCa)BCO is higher than that in (YCa)BCO. On the other hand, the width of Ca-poor channels is almost the same.…”