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Stability of the low-temperature tetragonal phase in La[sub 2[minus]x]Ba[sub x]CuO[sub 4] and related compounds

Conference · · Journal of Superconductivity; (United States)
OSTI ID:7070524
In La[sub 2[minus]x]Ba[sub x]CuO[sub 4] (LBCO), the structural transition to a low-temperature tetragonal phase below 60 K and suppression of superconductivity are observed when the carrier density is p [approximately] 1/8 per copper. The replacement by divalent ions smaller than Ba[sup 2+] suppresses the static deformation of the lattice. We have found that the variations T[sub d2], and superconducting transition temperature Tc are quantitatively characterized by the averaged ionic radius at the La site or lattice parameters. This aspect of substitution could be regarded as the effect of chemical pressure, since similar variations have been reported on applying hydrostatic pressure. In La[sub 2[minus]x[minus]y]Nd[sub y](Ba, Sr)[sub x]CuO[sub 4], T[sub d2] increases with increasing y in a wide range of p while Tc is suppressed only at p approximately 1/8. The structural transition at T[sub d2] here should be ascribed mainly to the crystallochemical origin. 12 refs., 2 figs.
OSTI ID:
7070524
Report Number(s):
CONF-930710--
Conference Information:
Journal Name: Journal of Superconductivity; (United States) Journal Volume: 7:1
Country of Publication:
United States
Language:
English