In situ growth of epitaxial Bi2Sr2CaCu2O8−x and Bi2Sr2CuO6−x films by pulsed laser ablation

Abstract

Pulsed-laser ablation has been used to grow epitaxial films of Bi2Sr2CaCu2O8−x (Bi-2212) and Bi2Sr2CuO6−x (Bi-2201) on (001) MgO with entirely in situ processing. The films’ layer-stacking sequence, microstructure, and superconducting Tc are highly sensitive to the growth temperature and deposition rate. Pure Bi-2212 films exist over only a narrow temperature range. Pure Bi-2201 films appear at higher growth temperature, while lower growth temperature enhances the Bi-2223 phase, though it is mixed with Bi-2212. The phase homogeneity, in-plane connections among grains, and superconducting Tc of Bi-2212 grown at a given temperature are greatly improved by reducing the deposition rate. Epitaxial Bi-2212 films grown at 740 °C and 0.5 Hz (∼0.05 nm/s) have Tc0 (R=0)=71 K, with Jc∼8×105 A/cm2 at 50 K and Jc∼5×106 A/cm2 at 4.2 K.

The effects of the post-annealing time on the growth mechanism of Bi2Sr2Ca1Cu2O8+∂ thin films produced on MgO (100) single crystal substrates by pulsed laser deposition (PLD)

“…The calculation of critical current density for Bi-2212 thin film produced via PLD is a rare issue in the literature. However, all maximum J C values for the film produced are comparable and better than those of some other recent studies [20,31,32]. Calculated J C value of the thin film annealed for 30 min explicitly demonstrates a better performance with increasing magnetic field up to 1000 Oe, compared to those of other films and then it starts to decrease comparatively.…”

Materials Informatics Reveals Unexplored Structure Space in Cuprate Superconductors

“…From the results presented here, we believe that the 3D strain engineering of Bi2201 or Bi2212 systems are of particular interest because they lie at the base of the unexplored region with >2.5Å apical distances (Figure 3E). 3D strain engineering using VAN is suitable for Bi2201 and Bi2212 because they can be made in situ via epitaxial growth methods, [33,34] however, other methods such as nonlinear phononics might also be appropriate. [35] Such experiments would allow greater insight into whether the high Tcs of Hg and Tl based cuprates are due to structural effects from the large apical distance or intrinsic electronic effects of the Hg and Tl cations.…”

MBE Growth of High Tc Superconductors

“…[94] Several groups have reported unusual x-ray patterns from Bi-Sr-Ca-Cu-O films grown by sputtering,j364] [ 365] shuttered ion beam sputtering, [ 366] laser ablation,j367] [ 368] and shuttered MBE. [ 88] The growth of superlattices was not attempted in these growths, so the strange x-ray patterns observed were at first not understood.…”