Relation between incommensurate modulation and Tc in Bi-Sr-Ca-Cu-O superconductors

Z.C. Kang , O. Monnereau , F. Remy , S. Spas , A. Casalot , J.P. Sorbier , A. Fournel , C. Boulesteix

Samples of the normal composition (2212) have been heated to 880, 904, 925, 940 and 950 °C, then cooled at 2 °C/Hour to obtain small single crystals. The resistivity of these samples was measured. Tc is lowest (86 K) for the lowest treatment temperature and highest (94 K) for the highest treatment temperature. The samples have been characterized by microanalysis and microdiffraction. An incommensurate modulation always occurs along (or close to) b* with different possible q* values (q* = 2 b*/4.80, q* = 2 b /9.89). The incommensurate phase, with Tc = 94 K and standard (2212) composition, is approximately sinuoisdal with only one satellite. The incommensurate phases in the unsinusoidal region, with several harmonic satellites, have 2 b*/q* values close to integer 10, a composition ratio deviation for the Sr, Ca, and Bi cation, and a lower Tc (86 K). A comparison with previous results has been performed.

Mots clés: bismuth compounds; calcium compounds; crystal atomic structure of inorganic compounds; high temperature superconductors; strontium compounds; superconducting transition temperature

Domaines: Articles anciens

Z.C. Kang, O. Monnereau, F. Remy, S. Spas, A. Casalot, et al.. Relation between incommensurate modulation and Tc in Bi-Sr-Ca-Cu-O superconductors. Journal de Physique, 1989, 50 (10), pp.1227-1240. ⟨10.1051/jphys:0198900500100122700⟩. ⟨jpa-00210991⟩