Stabilization of a new superconducting phase by low temperature fluorination of La2CuO4

Article abstract of DOI:10.1016/0921-4534(90)90491-V

When La₂CuO₄ is treated with pure F₂ gas at 200°C, the X-ray diffraction pattern of the resulting product is characteristic of a new single phase derived from the K₂NiF₄-type structure. An enhancement of the orthorhombic distortion relative to the starting oxide is observed with: a=5.342 angstrom; b=5.436 angstrom and c=13.192 angstrom. Both weight uptake and increase of the c unit cell constant could be consistent with an incorporation of fluorine atoms in the lattice. This new compound is superconducting at T_c=40 K with H_c1' 700 Oe and exhibits a strong diamagnetic susceptibility (X_g= -6.13 × 10^-3 emu/g) at 6 K under an applied field of 1 Oe.