Experimental study ofLa1Ba2

Yi Song

¹

,

John P. Golben

²

,

S. Chittipeddi

³

et al.

Magnetism, Superconductivity, and Chemical Substitutions in YBa2Cu3O7-δ

“…41 Under restricted synthesis conditions, a superconduct-ing onset temperature of 95 K and zero resistance temperature of at least 80 K have been attained in LaBa 2 Cu 3 0 7^. Surprisingly, studies of oxygen content 43 ' 44 show that while increasing the oxygen stoichiometry to y =7-8=7.1-7.4 is possible in LaBa 2 Cu 3 0 7 . I La I ) 2 Cu 3 0 7 .…”

“…41 " 46 Such structural deviations are generally manifested by the degree of orthorhombic distortion, although complications due to competing phases, including superstructures of the same stoichiometry, have been identified. 43 As a result of the larger size and lower charge of the Ba 2+ ion, the nearby Cu-O bond angles and distances would be reduced, with possible significance for superconductivity in the C u 0 2 planes. 42 Because the La 3+ ion is the largest trivalent ion in the rare-earth series, it most readily substitutes for the larger Ba 2+ ion; such compatibility is also evident in the Y(Ba 1 .…”

Effect of Processing on the Structure, Oxygen Content, and Superconductivity of LaBa2Cu3Oy

“…4,22 If the ionic radius, per se, is a major factor that causes the substitution of Ba 2+ ions by La 3+ ions, the ordering of La 3+ and Ba 2+ ions should be independent of the atmosphere. However, a reducing atmosphere and high temperature were found to be very effective in creating La 3+ and Ba 2+ order, 3,4,[9][10][11] which implies that oxygen removal in a reducing atmosphere at a high temperature has a crucial role in creating La 3+ and Ba 2+ ionic order.…”