Low temperature microstructure and phase transitions in La2−xSrxCuO4 and La2−xBaxCuO4

XAFS study of the low-temperature tetragonal phase ofLa2−xBaxCuOHaskel1, Stern2, Doğan3 et al. 2000Phys. Rev. B527440View full textAdd to dashboardCite

“…While indications of structural disorder in the LTT phase of La 2Ϫx Ba x CuO 4 have been previously reported, e.g., convergent beam electron diffraction studies 76 at Tϭ15 K showed lattice parameter variations on a Ϸ100Ϫ300 Å scale, our measurements provide detailed information on the nature of intrinsic disorder at length scales comparable to the superconducting coherence length, SC Ϸ10 Å . This information should provide a more quantitative base for a better assessment of the role played by disorder in determining normal and superconducting properties of La 2Ϫx Ba x CuO 4 .…”

Mesoscopic Twin Patterns in Ferroelastic and Co-Elastic Minerals

“…Examples of this are GdBa 2 Cu 3 O 7 , YBa 2 Cu 3 O 7 , Pb 3 (PO 4 ) 2 and feldspar (Smith et al 1987), and La 2-x Sr x CuO 4 (Chen et al 1991). In all of these cases the two halves of the split needle were the same but each half was asymmetric, the needle tips being displaced towards the centre line of the pair.…”

A survey of the Van Hove scenario for high-tc superconductivity with special emphasis on pseudogaps and striped phases

“…It was initially thought that, since the LTT phase is tetragonal, this transition should be clearly marked by the disappearence of twinning in the LTT phase. Instead, there appeared to be no change in the pattern of twins at the transition [455,456]. In fact, the LTT phase has orthorhombic symmetry within a single CuO 2 layer, but the global symmetry becomes orthorhombic due to the interlayer stacking.…”

“…63). Near this filling, earlier studies found that the holes form two types of domains, one of LTO phase with optimal T c and the other of LTT phase with reduced T c [896], with domain size ≈ 300Å [455]. (The orthorhombic domains have greatly reduced orthorhombicity, and may be of Pccn rather than LTO symmetry [457].)…”

“…A careful TEM study of the LTT-LTO transition [457] showed that the LTT APB's readily transform into APB's and twin boundaries of the LTO phase by a simple O tilting, without changing their locations. Thus, the microtwinning, which is typically observed in doped LSCO [455], may be a direct manifestation of the dynamic JT effect. In another TEM study of the LTT phase, Zhu, et al [458] find a domain pattern which they interpret in a similar fashion, Fig.…”